FAMILY I.
Pteropoda. Six genera

Some genera of this family are without a testaceous covering, and are mentioned only for the sake of preserving the family entire.

1. HyalÆa. Venus’s Chariot. Two species.

This genus derives its common name from a fancied resemblance to a miniature triumphal car.

Shell very thin, transparent, symmetrical, convex below, flat above, valves unequal, form tricuspidated, cleft at the sides, open like a cleft anteriorly, and tridentated posteriorly; summit truncated.

H. tridentata. The three-toothed HyalÆa.

Transparent, horn-coloured, globular; tridentated posteriorly; summit and two posterior sides open; finely striated transversely.

2. Clio. Has no Shell. Two species.

3. Cleodora. Two species.

Shell gelatinous, cartilaginous, transparent, in shape of a reversed pyramid or lanceolate truncated, only open at the summit.

C. pyramidata. The pyramidal Cleodora.

Like a pyramid, triangular, thin, transparent; aperture obliquely truncated.

4. Limacina. One species.

Shell papyraceous, very fragile, planorbis form, sub-carinated, involuted rather obliquely, in such a manner as to be deeply and largely umbilicated on one side, and the spine slightly projecting and pointed on the other; aperture large, entire.

L. helicialis. The Helix-like Limacina.

Thin, fragile, spiral; the volutions united in a discoid form.

5. Cymbulia. The Slipper. One species.

Shell or case cartilaginous, transparent, conical posteriorly where the animal adheres, and prolonged above like a long hollow semi-cylinder, under which the animal can take shelter.

C. Peronii. Peron’s Cymbulia.

Shell shaped like a shoe, somewhat gelatinous or cartilaginous, very transparent crystalline, oblong pointed at the vertex, truncated at the base.

6. Pneumodermon. Has no shell. One species.

FAMILY II.
Phyllidiacea. Four genera.

1. Phyllidia. Three species.

The animals of this genus are covered with a coriaceous skin, but without a shell.

2. Chitonellus. Two species.

Formerly classed with the Chiton; but as the testaceous plates of this genus are never joined, the two may be easily distinguished.

Shell elongated, multivalve; alternate pieces generally longitudinal; sides naked.

C. striatus. The striated Chitonellus.

StriÆ radiating from the apex of each valve; margin serrated; base of the last valve obtuse.

C. larvÆformis. The Caterpillar Chitonellus.

More or less cylindrical, almost naked; the valves of the shell very small, and almost entirely concealed under the skin; tufts hairy or silky between the parts of the valves near the margin.

3. Chiton. Six species.

This genus was so called from the resemblance of its testaceous covering to a coat of mail. The form of the Chiton is very similar to a well-known insect called the woodlouse, found in decayed timber; it generally adheres to rocks, or lies rolled up like a ball among seaweed and stones. In length it seldom exceeds an inch, except in tropical climates, where they are sometimes three or four inches long. In general there are eight valves, the termination of which is surrounded by a scaly or rough ligament, which enables the animal to expand or contract its shell freely. It presents a great variety of colour; in general it is dark brown, overcast with a shade of green, but some are beautifully variegated with pink, yellow, blue, or red; interior green or whitish.

Shell more or less elongated, consisting of a longitudinal series of eight very symmetrical calcareous pieces, more or less curved, and round at both extremities; summit more or less marked, and when imbricated, always from front to rear.

C. squamosus. The scaly Chiton. Pl. 1, fig. 1.

Depressed, valves large, carinated, well imbricated; the interstices offering well-marked lateral spaces; the border of the mantle regularly scaly.

C. marginatus. The marginated Chiton. Pl. 1, fig. 2.

Valves carinated and projecting over each other; finely shagreened, with a dusky reddish-brown margin.

C. fascicularis. The fasciculated Chiton. Pl. 1, fig. 3.

Valves more narrow, imbricated, without distinct spaces; lateral parts of the skin naked or hairy, but always provided with silky or hairy tufts disposed in pairs between the junctions of the valve.

C. spinosus. The spiny Chiton. Pl. 1, fig. 4.

Shell beset with long, thin, curved, tubular, hairy, blackish spines.

4. Patella. The Limpet or Dishlike Shell. Forty-five species.

The Patella of LinnÆus was divided by Lamarck into several distinct genera, and now comprehends only such shells as are of a conical form, with an imperforated summit. The anterior is that part to which the summit inclines, and is always more narrow than the posterior part.

It derives its name from its resemblance to a little dish; the colour and structure are various; some are smooth, others granulated, and many are covered with elevated tuberculated ribs. The exterior is sometimes of a pale fawn colour, and the interior of a bright pink; some have a silvery hue, but the more general colour is bluish white or light brown.

This genus of shells is very numerous in all seas, but chiefly in hot countries, where they are found of a larger size; they generally adhere by their base to rocks, stones, and marine substances, from which it is difficult to detach them.

Shell oval or circular, sub-conic; summit right or more or less recurved anteriorly; the cavity simple, entire, more or less deep; the margin complete and entirely horizontal; a narrow muscular impression.

P. vulgata. The common Patella. Pl. 2, fig. 1.

Conic, summit obtuse and vertical; sometimes ribbed from the vertex to the margin with divergent striÆ, sometimes striated without ribs; exterior dark brown or greenish, internal blue or purple radiations.

P. compressa. The compressed or flat-sided Patella. Pl. 2, fig. 2.

Oval, elongated, compressed on the sides, having the summit sub-anterior, well marked, and curved; exterior fawn colour, interior of a silvery hue.

P. deaurata. The golden red Patella. Pl. 2, fig. 3.

Sub-conic, summit more anterior, with a slight forward inclination; colour yellowish red.

P. cochlear. The spoonlike Patella. Pl. 2, fig. 4.

Depressed, the summit hardly marked, and much more narrow in front than behind; exterior brownish, interior light blue.

P. scutellaris. The buckler Patella. Pl. 2, fig. 5.

Depressed, summit sub-anterior, radiated from the summit to the margin; brown colour, with a yellowish band parallel to the margin.

P. pectinata. The pectinated Patella. Pl. 2, fig. 6.

Oval, summit well marked and anteriorly inclined; ribbed from the summit to the margin, which is slightly convex in the middle.

P. cymbularia. The cymbular Patella. Pl. 2, fig. 7.

Oval, thin, pearly, with a festooned margin; summit nearly marginal; colour white, shaded with very light brown.

FAMILY III.
Calyptracea. Seven genera.

The genera that constitute this family were separated by Lamarck from the Patella of LinnÆus.

1. Parmaphora. The Duck’s-bill Limpet. Three species.

The characteristic distinctions of this shell were first pointed out by De Blainville.

Shell elongated, very depressed; the summit greatly post-medial, and evidently inclined behind; aperture as large as the shell; the lateral edges straight and parallel, the posterior rounded, the anterior sharp and notched in the middle; muscular impression large, elongated oval, slightly open in front.

P. Australis. The Australian Parmophorus.

Shell oblong, depressed; vertex slightly recurved; striated concentrically; one margin rounded, and the other truncated.

2. Emarginula. The Slit Limpet. Four species.

Most of the shells of this genus are small; some are elevated, and others of a widely-depressed conical form.

Shell conical, recurved; summit entire; slit, or more or less hollowed on the anterior side; a muscular impression in form of a horseshoe, open behind and thicker at the beginning.

E. Blainvillii. Blainville’s Emarginula.

Shell with the notch or slit in the middle of the back, and not extending to the margin.

E. fissura. The slit Emarginula. Pl. 32, fig. 5.

Oval, compressed, summit well marked, with reticulated striÆ and ribs; fissure extending half way from the margin to the summit; exterior light brown, interior white.

E. marginata. The marginated Emarginula.

More compressed than the preceding; summit distinct, anterior margin formed like a gutter.

3. Fissurella. The Keyhole Limpet. Nineteen species.

The perforation not being perfectly round, but generally ovate oblong, procured for this genus its common name, by which it is easily distinguished.

Shell simple, conical, depressed, recurved; summit perforated a little anterior in an oblong or oval manner, like a keyhole; the exterior surface ribbed longitudinally, slightly striated transversely.

F. nimbosa. The scaly-ribbed Fissurella.

Species of which the middle part of the edges of the aperture is hollowed in such a manner that, when placed on a level surface, they touch only at the extremities.

F. rosea. The rosy Fissurella.

Species more depressed, edges bent up lengthwise, forming a kind of canal.

F. GrÆca. The Greek Fissurella. Pl. 32, fig. 1.

Conical, ovate oblong; striÆ cancellated and elevated; sections tuberculated; exterior yellowish brown or clouded, interior white or light blue.

4. Pileopsis. The Caplike Limpet. Four species.

Easily distinguished by its form, which gave rise to the common name.

Shell oblique, sharp pointed; cone bent forward, with a recurved, almost spiral summit, finely striated longitudinally and slightly wrinkled transversely; aperture a round oval; the margin at the base nearly round, more or less regularly crenated and indented, interior with a lengthened, arched, transverse muscular impression.

P. ungarica. The Fool’s Cap.

Conical, vertex slightly spiral, pointed, and recurved; exterior pale fawn colour, and the outer margin bordered with a fringed epidermis; interior sometimes of a very bright pink or rose colour.

5. CalyptrÆa. The Cup and Saucer Limpet. Four species.

This genus of shells is remarkable for having in the interior cavity a transverse funnel or tongue-shaped testaceous appendage, from which originated its common name.

Shell conic, base orbicular; summit vertical and imperforated; cavity deep, having at its interior summit a tongue-like appendage. This appendage is sometimes vertical and sometimes like a horseshoe, having on it a muscular impression of variable form.

C. extinctorium. The extinguisher CalyptrÆa.

Species in which the internal appendage is horn-shaped; colour brownish.

C. equestris. The equestrian CalyptrÆa. Pl. 32, fig. 4.

Species in which the internal appendage is like a horseshoe, open in front.

C. tectum-sinense. The Chinese roof CalyptrÆa.

Shell formed of separate, transverse, irregular round laminÆ of uniform size, attached to each other by the summit on the exterior of each, presenting the appearance of a number of small flat PatellÆ piled one on the other; colour yellowish, margin entire, very glossy within.

6. Crepidula. The Slipper Limpet. Six species.

Very similar to the Navicella, but distinguished from it by not having an operculum.

Shell irregular, form very variable, depressed or compressed; spire obliquely inclined to one side; margin entire; cavity large, divided by a horizontal partition, which gives it the form of a half-decked boat.

C. porcellana. The brown-spotted Crepidula.

Shell thick, flat, summit not spiral.

C. aculeata. The prickly Crepidula.

Oval, brown, roughly striated, vertex recurved, interior blue or purple.

C. sub-spirata. The sub-spiral Crepidula. Pl. 32, fig. 2.

Species almost round, summit sub-spiral; colour yellowish white, with a bluish tinge towards the summit.

7. Ancylus. The Lake Limpet. Two species.

This is a fresh-water shell, found in the lakes of Europe.

Shell thin and brittle, obliquely conical; summit pointed and recurved; margins simple, base oval and smooth.

A. oblongus. The oblong Ancylus.

Aperture elongated, vertex turned to one side, striated concentrically; exterior pale yellowish colour, interior light blue.

A. fluviatilis. The river Ancylus. Pl. 32, fig. 3.

Simple, oval, almost symmetrical; summit pointed, compressed, very distinct; bent back a little to the right, but not marginal; the edges of the aperture entire and effuse.

FAMILY IV.
Bullacea. Three genera.

1. Acera. Has no shell. One species.

2. BullÆa. One species.

Formerly classed with the Bulla, but separated from it on account of the shell being entirely covered by the animal, and never externally visible.

Shell oval, thin, fragile, more or less involuted on one side, rendering the aperture more or less wide.

B. aperta. The open BullÆa. Pl. 17, fig. 5.

Shell interior and very incompletely involuted, without spire or columella; sub-orbicular, white, transparent, faintly striated, and slightly wrinkled; almost entirely open.

3. Bulla. The Bubble. Eleven species.

The great confusion that existed in this genus, as classed by LinnÆus, has been elucidated by the division and classification of Lamarck. This genus derived its name from the resemblance which some of the smaller species have to a bubble of water. Its shells are found in almost all parts of the world.

Shell external, oval, involuted; aperture very large, open the whole length of the shell, and generally wider at the base; outer edge sharp and smooth; summit umbilicated.

B. aplustre. The streamer-like Bulla. Pl. 17, fig. 7.

Species completely involute; the spire very distinct, visible, but not projecting, with a kind of thickening at the anterior part of the columellar edge.

B. lignaria. The woodlike Bulla.

Species sub-involute, no visible spire either within or without, but narrowed towards the top when it is slightly umbilicated; yellowish brown colour, with transverse pale striÆ.

B. hydatis. The watery Bulla.

Species more solid, thicker, almost entirely involute; whorls of the spire slightly visible in an umbilicus projecting interiorly from the summit.

B. naucum. The sea-nut Bulla.

Species thin; the whorls of the spire visible externally, but without projection, and with a suture as if caniculated without thickening at the anterior part of the columellar edge.

B. fragilis. The fragile Bulla.

Species very thin, rather involute; the whorls of the spire distinct within as without; the suture deep, angular, and cleft in a greater or less part of its length.

FAMILY V.
Aplysiacea. Two genera.

1. Aplysia. Three species.

This genus may almost be said to have no testaceous covering, as it appears more like the element of a shell.

A. depilans. The bald Aplysia.

Shell dorsal, semicircular, of a thin yellow cartilaginous substance.

2. Dolabella. Two species.

Closely allied to the Aplysia; it is a singularly formed shell, difficult to describe, as it contains few of the characteristics which distinguish other shells.

Shell rudimentary, entirely flat, sub-spiral, with a summit thick and very callous.

D. Rumphii. Rumphius’s Dolabella.

Base thick, callous, and sub-spiral; dilated above, thin, and wedge-shaped.

1. Onchidium. Has no shell. Two species.

2. Parmacella. One species.

Lamarck has given a description of the animal of this genus, but only mentions that the scutcheon contains a shell or solid crustaceous body.

3. Limax. Four species.

The animal belonging to this genus is furnished with a coriaceous shield, wrinkled.

4. Testacella. One species.

Shell external, very small, ear-shaped; very depressed, summit inclined posteriorly, not spiral; aperture oval, very large; the left edge sharp, a little rolled inward, especially behind.

T. Haliotidea. The Haliotis-shaped Testacella. Pl. 17, fig. 6.

Answering to the above description; very thin, transparent, and yellowish.

5. Vitrina. One species.

Shell proportionally very small, extremely thin, pellucid, almost membranous, oval or sub-globular; spire very short, of which the last whorl is very large; aperture large, semilunar; the edges sharp; the left edge arched, and extending itself interiorly to the summit.

V. pellucida. The pellucid Vitrina. Pl. 17, fig. 3.

Extremely thin, pellucid, and glossy; depressed, spire very short; aperture large and oval; colour pale yellowish green.

FAMILY VII.
Colimacea. Eleven genera.

1. Helix. The Snail. One hundred and seven species.

According to the systematic arrangement of Lamarck, this genus now consists of shells with peculiar characteristic distinctions.

By LinnÆus, marine, land, and fresh-water shells were united in this genus, and so confounded that the naturalist would often look in vain for the distinguishing characters which would enable him to class and determine the genus of the object under examination.

Notwithstanding the divisions of Lamarck, its species are numerous; the shells are terrestrial, and found in all parts of the globe; some are rare and beautiful.

The term Helix was given to this genus from the spiral form of the shell.

Shell extremely variable in form, generally globular, sometimes ventricose, conoid, never turriculated; summit constantly obtuse and rounded; aperture generally of a medium size, but sometimes very large or very small, always modified by the turn of the spire; oval, semilunar, more wide than long, edges disunited, entering but very little into the formation of the interior; the right lip or margin thickened or reflected.

H. algira. The yellow Snail. Pl. 18, fig. 8.

Species shaped like a Planorbis, rough or hairy, more or less largely umbilicated, margin sharp.

H. Naticoides. The Natica-shaped Snail. Pl. 18, fig. 7.

Species ventricose.

H. obvoluta. The small white-lipped Snail. Pl. 18, fig. 9.

Species more or less depressed, umbilicated, Planorbis-shaped, the edges of the aperture thickened, callous, and even toothed.

H. conoides. The cone-shaped Snail. Pl. 18, fig. 4.

Species conoidal; the turns of the spire rounded.

H. pomatia. The edible Snail.

Species sub-globular, not umbilicated; the margin of the aperture thickened; aperture covered with a calcareous lid resembling an operculum.

H. nitida. The pellucid Snail.

Species depressed, more or less largely umbilicated; the edges sharp, but always thin and shining.

H. nemoralis. The grove Snail.

Species imperforated, semi-globular, thin, and sub-pellucid; not umbilicated, with a light inflexion at the place of the junction of the columella with the margin of the aperture; colour various, inner margin white or reddish brown; volutions five, with several dark brown bands.

H. Carthusiana. The Carthusian Snail.

Species sub-depressed, sub-umbilicated, with a sharp edge, thickened within by a roll.

H. arbustorum. The orchard Snail.

Sub-globular, sub-pellucid, sub-umbilicated, five volutions, finely striated longitudinally; mottled with greenish yellow, streaked with deep chestnut, a broad brown band commonly at the edge of the outer lip, and running round through the volutions to the apex.

2. Carocolla. Eighteen species.

All terrestrial shells in this genus, taken from the LinnÆan Helix on account of the peculiarity of the shell, which is orbicular, more or less flat on the upper part; the circumference of the shells constantly carinated or sub-carinated; aperture ovate, transverse, contiguous to the axis of the shells; outer lip sub-angular, sometimes toothed within.

C. lapicida. The stone Carocolla. Pl. 19, fig. 1.

Species discoid, very umbilicated; edges thick, but not toothed; beautiful bands.

C. elegans. The elegant Carocolla.

Species with a conical spire a little elevated, the base flat, the aperture square, with sharp edges.

C. labyrinthus. The winding Carocolla.

Species discoid, umbilicated, with the aperture toothed.

3. Anostoma. Two species.

An extraordinary shell, sometimes called the antique lamp from its form.

Shell orbicular, the spire convex and obtuse; aperture round, toothed within, grinning, turned upward to the spire; margin reflected.

A. depressa. The depressed Anostoma.

Sub-globular, depressed and sub-carinated in its circumference, not umbilicated; aperture round, the margin continued by a callosity, toothed, thickened, and turned towards the back of the shell.

A. globulosa. The globular Anostoma.

Globose, with two small punctures, one on each side of the lip; slightly carinated, smooth, and white; margin reflected.

4. Helicina. Four species.

A terrestrial shell, distinguished from the Helix by its transverse callous columella; depressed and diminished in thickness at the lower part.

Shell sub-globular or conoid, spire low, a little depressed; aperture semi-ovate, modified by the last turn of the spire; the edge of the aperture sharp or a little reflected in a roll, the left edge enlarged at its base in a large callosity, which entirely covers the umbilicus and joins obliquely with the columella, which is twisted and a little projecting; the operculum horny, complete, sometimes calcareous externally.

H. Neritella. The Nerite-shaped Helicina. Pl. 19, fig. 4.

Species yellowish white, finely striated, the edge reflected in a roll.

H. striata. The striated Helicina.

Globular, striated, the right edge sharp, but reflected; the umbilical callosity rather thick, the operculum calcareous and solidified by a marginal roll and a vertical crosspiece.

5. Pupa. Twenty-seven species.

These shells are generally very small, some not more than an eighth of an inch in length; chiefly terrestrial.

Shell cylindrical, elongated, or sub-globular, ordinarily ventricose: summit obtuse; the turns of the spire numerous, almost equal; aperture round or oval, with margins almost equal, expanded, reflected; one or two plaits on the columellar edge, and several teeth, varying in number on the right margin.

P. Lyonetiana. Lyonet’s Pupa. Pl. 18, fig. 5.

Species cylindrical, obtuse, aperture compressed and distorted by the last whorl in its adult state making suddenly a gibbous inflection to the left.

P. muscorum. The moss Pupa.

Species very small, oval or more or less spherical, obtuse, light brownish colour; aperture large, with one tooth; volutions convex; outer lip white and reflected.

P. mumia. The double-toothed Pupa. Pl. 19, fig. 2.

Species cylindrical, obtuse at both ends, aperture semi-ovate, with two teeth.

6. Clausilia. Twelve species.

Remarkable for having the termination of the lower whorl quite detached from the base of the shell.

Shell cylindrical, elongated, a little ventricose in the middle, generally fusiform, summit obtuse, the last turn smaller than the preceding; aperture small, irregular, oval; at least one plait, posterior to the columella, increasing with age so as to be separated, and forming at the posterior angle of the aperture a rounded sinus.

C. lÆvis. The smooth Clausilia. Pl. 19, fig. 3.

A regular type of this genus.

C. papillaris. The pimpled Clausilia.

Pellucid, finely striped longitudinally, the margins of the volutions papillose; aperture with two plaits; brownish colour.

7. Bulimus. Thirty-four species.

The shells of this beautiful genus are all terrestrial, and differ from the Helix and Bulla of LinnÆus in never being of an orbicular shape. The animals inhabiting them are said to be oviparous, and have eggs nearly as large as those of a pigeon.

Shell oval, oblong, sometimes sub-turriculated; the summit of the spire obtuse, and the last turn much greater than all the others taken together; aperture oblong oval, the edge disunited; the right reflected outward in adults; the columella smooth, with an inflection in the middle, at the point of junction of the columella with the mouth of the aperture which it forms.

B. montanus. The mountain Bulimus.

Ovate oblong, umbilicated, slightly striated longitudinally, with several convex volutions; aperture semi-oval; brownish colour; outer lip white and reflected.

B. hÆmastomus. The rose-lipped Bulimus.

Species oval or of ordinary form.

B. ventricosus. The ventricose Bulimus.

Species ventricose, from which circumstance it derived its name.

B. radiatus. The radiated Bulimus. Pl. 19, fig. 7.

Species turriculated.

B. citrinus. The citron Bulimus.

Species sinistral.

B. multifasciatus. The many-banded Bulimus.

Species slightly umbilicated.

This likewise is an elegant genus of shells, classed by LinnÆus with the Bulla. They are the largest land-shells known, and greatly resemble the Bulimus, but never have their lips reflected or thickened. Sometimes the last whorl is compressed and attenuated at the base, and sometimes ventricose and not compressed.

Shell in form very variable, but generally sub-turriculated, ventricose, striated longitudinally; the summit papillose; aperture a little variable, but never thickened or reflected; the right edge always acute, the columellar margin rather strongly hollowed, entirely formed by the columella, of which the anterior extremity is constantly open and truncated.

A. Virginea. The Virginian Achatina.

Smooth, conoid, with aperture almost round; very short, grayish white, with red and black transverse bands; columella rose-coloured, with one plait; volutions ventricose; inside of the lips bluish; a transverse callosity in the interior.

A. zebra. The zebra Achatina. Pl. 18, fig. 1.

Species thin, oval, sub-ventricose, spire prominent, striped like a zebra.

A. glans. The acorn Achatina. Pl. 18, fig. 2.

Species sub-turriculated, of which the last whorl is attenuated anteriorly.

A. columnaris. The columnar Achatina. Pl. 18, fig. 3.

Species evidently turriculated.

9. Succinea. Three species.

A terrestrial shell, though the animal that inhabits it is almost amphibious; it greatly resembles the Bulimus, but is easily distinguished by never having the lip reflected or thickened.

Shell very thin, translucid, ovate-oblong, with a conical-pointed spire formed of a small number of whorls; aperture very large, oval, oblique; the edges disunited; the right always acute, the left acute and arched, formed by the columella.

S. amphibia. The amphibious Succinea. Pl. 24, fig. 4.

Species elongated, very thin and pellucid; spire short; aperture expanding; amber colour.

10. Auricula. Fourteen species.

This genus was so called from the resemblance which the aperture bears to the shape of an ear; many of the species are named from their resemblance to the ears of particular quadrupeds. It is a land-shell, found chiefly in the East and West India Islands.

Shell thick, solid, more or less smooth, oval, oblong, spire short and obtuse; aperture entire, oblong, enlarged, ear-shaped, much contracted behind; edges disunited; right lip sometimes thick and outwardly reflected; the left or columella with one or more teeth or thick callous plaits.

A. JudÆ. Judas’s Ear. Pl. 19, fig. 6.

Species thick, oblong, conical, with minute decussated striÆ and granulations; light brown; two plaits on the columella; right outwardly reflected.

A. scarabÆus. The Beetle’s Ear.

Species of which the columella has three plaits, and the whole internal side of the right edge denticulated.

A. myosotis. The dwarf Auricula.

Species minute, with two plaits on the columella, and one tooth behind.

A. Sileni. Silenus’s Ear.

Species very small, without plaits or teeth.

11. Cyclostoma. Twenty-eight species.

A terrestrial shell, varying considerably in form, but distinguished by a round aperture, reflected lip, and horny operculum.

Shell more or less elevated, volutions rounded, summit papillose; aperture round, the edges united circularly and reflected; the left having its origin very detached from the spire.

Operculum calcareous, complete, not spiral; summit sub-central.

C. elegans. The elegant Cyclostoma. Pl. 19, fig. 5.

Species with spire slightly elevated, ovate, conical, umbilicated; volutions convex; finely striated transversely.

C. fasciata. The banded Cyclostoma.

Species with spire very elevated.

C. Planorbula. The Planorbis-shaped Cyclostoma.

Species with spire very depressed.

FAMILY VIII.
LymnÆcea. Three genera.

1. Planorbis. Twelve species.

Taken from the Helix of LinnÆus to distinguish the aquatic from the terrestrial shells. This genus is found in fresh water, and has no operculum.

Shell thin, often sinistral, discoid, or involuted almost in the same vertical plane; the spire not projecting and entirely lateral, so that the shell is hollowed or depressed on each side; aperture small, transverse, with edges sharp, not reflected, disunited by the last whorl of the spire which modifies it; sometimes carinated.

P. carinatus. The keeled Planorbis.

Species with a keel; depressed, upper side concave.

P. corneus. The horny Planorbis. Pl. 20, fig. 4.

Species without a keel.

2. Physa. Four species.

This genus is generally heterostrophe (that is, with whorls turned to the left hand); found in fresh water; it greatly resembles the LymnÆa, but has not a widened aperture.

Shell often sinistral, oval, oblong, or globular, perfectly smooth; aperture oval, contracted posteriorly; the right edge sharp, advanced above the plane of the left edge; columella twisting obliquely, and enlarging to join itself to the anterior part of the columellar margin.

P. fontinalis. The fountain Physa. Pl. 20, fig. 2.

Volutions reversed, oval, ventricose, pellucid, horn-coloured; spire short and acute.

3. LymnÆa. Eleven species.

Shell aquatic, oval, turreted or conical, thin, smooth, spire pointed; aperture oval, entire; edges disunited, the left with a very oblique plait at the point of junction of the columella with the rest of the margin.

L. stagnalis. The pond LymnÆa. Pl. 20, fig. 1.

Ovate, ventricose; spire subulate and very acute; aperture large and ovate; horn coloured.

L. leucostoma. The shining LymnÆa.

Species sub-turreted, with the right edge thickened.

FAMILY IX.
Melanides. Three genera.

1. Melania. Sixteen species.

Likewise taken from the Helix of LinnÆus.

Shell fluviatile, covered with epidermis, oval, oblong; spire slightly pointed, more or less turreted; the margin of the whorls often surmounted by spires; aperture oval, entire; columella smooth and arched; closed by a thin, horny, complete operculum.

M. amarula. The crowned Melania. Pl. 20, fig. 3.

Covered with a black epidermis, under which the colour is deep chestnut; ovate oblong, with the whorls transversely keeled and coronated with triangular tubercles, from which emanate ciliated spines.

2. Melanopsis. Three species.

The shells of this genus are fluviatile, and distinguished from the Melania by having the upper part of the columella callous.

Shell oval or slightly sub-turriculated; aperture oval, without trace of tube, but hollowed anteriorly, without a posterior sinus; the columellar edge callous and rather deeply excavated; operculum horny, sub-spiral, rather complete.

M. Buccinoides. The Buccinum-shaped Melanopsis. Pl. 20, fig. 6.

Species turriculated; colour bluish white, clouded with purple; spiral whorls dentated.

M. costata. The ribbed Melanopsis.

Species sub-turriculated and ribbed.

M. lÆvigata. The polished Melanopsis.

Species ovate, smooth, chestnut colour.

This shell resembles the Melania, but is easily distinguished by having a sinus at the base and another at the summit.

Shell turreted, aperture oblong, closed by a horny operculum; right lip sharp, with a distinct sinus at the base and another at the summit; base of the columella inclined towards the right.

P. terebralis. The wimble Pirena.

Subulate, longitudinally striated, covered with a dark-brown epidermis; aperture white, outer lip expanded.

FAMILY X.
Peristomides. Three genera.

1. Valvata. One species.

This genus contains shells found in fresh water. Shell sub-discoid or conoid, umbilicated, spiral whorls rounded; summit papillose; aperture round, not modified by the last whorl; the edges completely united, sharp; operculum complete, horny, and orbicular.

V. piscinalis. The Pond Valvata. Pl. 20, fig. 5.

Small, globular, conoid, deeply umbilicated; summit obtuse; wrinkled longitudinally, covered with a yellowish epidermis.

2. Paludina. Seven species.

Generally inhabits fresh water, though some have been found where it is quite saline.

Shell conoid, covered with epidermis, spiral whorls rounded; rather longer than broad, edges united, always sharp; the commencement of the left edge immediately attached to the last whorl of the spire; operculum horny, complete, or marginal, not spiral, with concentral elements.

P. vivipara. The viviparous Paludina. Pl. 21, fig. 1.

Thin, ovate, ventricose, wrinkled longitudinally; body with three brown bands: covered with a greenish epidermis; aperture almost round.

3. Ampullaria. Eleven species.

This genus is evidently intermediary to the Paludina and the Natica. Its species are probably all fluviatile; some attain a great size.

Shell thin, globular, ventricose; umbilicus small, forming a compressed funnel-shaped aperture, without interior callosity; spire very short, the last whorl much larger than all the others together; aperture ovate, longer than broad, with margins united; right margin smooth and sharp; columellar lip thickened, projecting, and reflected over the umbilicus; operculum horny, rarely calcareous, thin, oval, not spiral, with concentric elements; summit sub-marginal, inferior, passing obliquely by the right edge of the aperture, but attached to the left.

A. Guyanensis. The Guiana Ampullaria.

Globular, thick, with unequal longitudinal striÆ; covered with brown epidermis; inside golden colour.

A. rugosa. The rough Ampullaria. Pl. 21, fig. 3.

Species dextral.

A. Guinaica. The Guinea Ampullaria.

Species sinistral.

A. carinata. The carinated Ampullaria.

Species sinistral, with a very large umbilicus, spirally carinated.

FAMILY XI.
Neritacea. Five genera.

1. Neritina. Twenty-one species.

Formerly classed with the Nerita, but separated from it because the Nerita is a marine shell, and those of this genus are fluviatile.

They are generally thin, smooth, or very finely striated; the right side of the aperture is not crenulated or dentated, and the animal dissolves the interior of the spire.

Shell thin, ovate, not umbilicated; aperture semilunar; inner lip reflected on the columella, and sometimes crenated; outer lip without teeth internally; operculum with a lateral tooth.

N. fluviatilis. The fresh-water Neritina.

Shell very small, oval; back convex, smooth, white, with black or brown spots; spire inclined, lateral lip slightly denticulated; right edge sharp, operculum very oblique.

N. zebra. The zebra or striped Neritina. Pl. 21, fig. 2.

Same as N. fluviatilis, but striped instead of spotted.

N. corona. The crown Neritina. Pl. 21, fig. 4.

Species provided with long spines, and with the columellar edge denticulated.

N. auriculata. The eared Neritina.

Species with the columellar edge denticulated; the two extremities of the right edge extending beyond the aperture, and forming with the callosity, which is reflected over the columella, a kind or ear, produced by the tentacular lobe of the animal.

N. perversa. The perverse Neritina.

Species shaped like a CalyptrÆa, with the superior summit vertical, spiral; the last whorl forming all the base of the shell.

2. Navicella. Three species.

A fresh-water shell, closely allied to the Neritina; it generally has the appearance of porcelain.

Shell ovate oblong, covered with epidermis, shaped like a Patella, summit not spiral, but straight, turned quite to the base, and concave beneath; no columella; the columellar edge replaced by a kind of sharp partition, which covers part of the aperture, with a sinus at its left extremity; muscular impression shaped like a horseshoe, open in front and interrupted behind; thin, calcareous operculum, with a subulate, lateral tooth adhering to the posterior margin; the other edges sharp.

N. elliptica. The oval Navicella.

Shell covered with olive epidermis, under which it is smooth, shining, spotted and streaked with purple, blue, or brown; spire curved, prominent, extending beyond the margin.

A marine shell, never spined, but variously striated. Some species of this genus are very beautiful; they are frequently worn as ornaments by the Indians.

Shell solid, thick, more or less globular, flat beneath, spire but little, if at all, projecting, not umbilicated; aperture large, semilunar, very entire; the external margin very much hollowed; the internal or columellar straight, sharp, and shaped like a partition, often dentated; operculum horny or calcareous, sub-spiral; the summit entirely marginal at its extremity, implanted by teeth more or less marked, and sunk in the columellar margin, on which it seems articulated.

N. peloronta. The bleeding-tooth Nerita. Pl. 21, fig. 5.

Thick, transversely sulcated; inner lip with two crenulations, with a bloody mark at their base; under lip with two notches near its internal upper edge; colour yellowish, tinged with red, with variously coloured bands.

N. exuvia. The exuvia Nerita.

Species with the inner lip toothed and tuberculated.

N. polita. The smooth Nerita.

Species with both lips toothed; beautifully distinguished by having three or four bright crimson bands, on a dark mottled ground, running in a parallel direction with the convolutions of the shell. A favourite Indian ornament.

A marine shell, formerly classed with the Nerita, but distinguished by being without teeth, and having an umbilicus modified by the callosity.

Shell smooth, rather thin, and not covered with epidermis; the spire evident, though low, umbilicated; the columellar edge not toothed, more or less callous, modifying the umbilicus; the right edge thin and not toothed interiorly; operculum calcareous or horny and smooth, semi-spiral, with concentric ribs fitting into a slight groove on the columella.

N. canrena. The Canrena Natica.

Sub-globular, smooth, umbilicus deep, bordered anteriorly by a kind of callous column; spire a little prominent; exterior fawn coloured, with bands and rays of reddish brown; interior white; operculum calcareous.

N. castanea. The chestnut Natica. Pl. 21, fig. 6.

Species with the umbilicus uncovered, and the operculum horny.

N. mamilla. The nipple Natica.

Species with the umbilicus entirely covered over by a large callosity; the spire papillose, and the operculum horny.

5. Janthina. Two species.

Formerly classed with the Helix, which it somewhat resembles in form, but properly separated, as it differs in every other respect.

It is a singular marine shell, often found in great numbers floating on the surface of the sea, suspended by a vesicular appendage, which stains the hand of a purple colour.

Shell sub-globular, ventricose, extremely thin and fragile; transparent, of a beautiful violet colour; the spire low, lateral, pointed, with sub-carinated whorls; aperture large, sub-angular, greatly modified by the last whorl of the spire; edges disunited, the left entirely formed by the columella, which is straight and continued beyond the base, the right edge sharp, often with a sinus in the middle.

J. communis. The common Janthina. Pl. 18, fig. 6.

Very fragile, aperture triangular, with a small notch on the margin of the outer lip; beautiful violet colour.

FAMILY XII.
Macrostomides. Four genera.

1. Sigaretus. Four species.

Distinguished from the Natica by the great width of the aperture, and its short spiral columella.

Shell oval, more or less thick, very depressed, spiral short, little elevated, lateral; aperture very extended, entire, the left edge reflected and sharp; two lateral muscular impressions very disunited.

S. convexus. The convex Sigaretus. Pl. 22, fig. 2.

Very thin, smooth, back convex, spire white, rather prominent; aperture very expanded; umbilicus rather deep; yellow, with a reddish tinge, transversely striated.

S. Haliotoideus. The Haliotis-shaped Sigaretus.

Species thick, solid, depressed; spire flattish, aperture exposing the whole of the interior.

2. Stomatella. Five species.

To be easily distinguished from the Stomatia by not having a transversal rib.

Shell very depressed, orbicular or oblong; imperforate; interior pearly; aperture very large, oval, longer than wide; the right edge effuse, dilated, and open; summit pointed and incurved.

S. imbricata. The imbricated Stomatella. Pl. 22, fig. 1.

Sub-orbicular, convex, sub-depressed, rough, covered with imbricated scales; colour grayish brown.

S. auricula. The ear-shaped Stomatella.

Species oval, elongated.

3. Stomatia. Two species.

Bearing a very great resemblance to the Haliotis, but is never perforated.

Shell ear-shaped, imperforate; oblong, spire elevated and recurved to one side; aperture entire, oblong; interior pearly; tuberculated, and with a transverse sub-carinated rib.

S. phymotis. The tumoured Stomatia. Pl. 22, fig. 6.

Elongated oval, striated, tuberculated; spire small, contorted; lip thin and sharp, colour white, interior pearly.

This genus is very beautiful, and derived its common name from its resemblance to the human ear. The exterior is generally tuberculated and loaded with marine substances, which gives it a rough and uncouth appearance, but the interior forms a splendid contrast by its natural iridescence. Each shell is furnished with a row of orifices near the margin, varying in number from eight upward; of these from three to seven are generally open, and the others close. These holes are made by the animal as it increases the size of the shell, to admit the passage of a short syphon.

They are found adhering to rocks like the Patella, and are detached with great difficulty.

Shell ear-shaped, pearly, recurving, very depressed, more or less oval, with spire very small, very low, almost posterior and lateral; aperture as large as the shell, with margins continued; the right thin and sharp, the left flat, enlarged, and sharp; a series of holes, complete or incomplete, parallel to the left margin; one large oval muscular impression.

H. asinina. The asinine Haliotis.

Internal margin very broad, inside pearly, smooth, shining, iridescent, reflecting green, pink, and orange; back clouded with brown and green; striated longitudinally.

H. costata. The ribbed Haliotis. Pl. 22, fig. 4, interior. Pl. 32, fig. 6, exterior.

Species with disk rounded anteriorly.

H. canaliculata. The channelled Haliotis.

Species with disk elevated by a large parallel rib, hollowed interiorly, and with the anterior margin more or less irregular.

H. tuberculata. The tuberculated Haliotis.

Aperture open the whole length of the shell; outer lip irregular, exterior reddish brown, striated longitudinally and wrinkled transversely, with a few raised tubercles; interior pearly, reflecting the most beautiful shades of pink, blue, green, and yellow.

FAMILY XIII.
Plicacea. Two genera.

1. Tornatella. Six species.

Shell thick, oval, convolute, the spire very short; the last whorl much larger than all the others united; the external thin, sharp, dentated interiorly; one or two large plaits on the columella, of which one serves to separate the two parts of the foot.

T. fasciata. The banded Tornatella.

Spire produced, apex acute, aperture straightened, with one plait on the columella; finely striated transversely, with two white transverse bands; colour purplish red.

T. coniformis. The cone-shaped Tornatella. Pl. 22, fig. 3.

Species like a cone; the spire entirely flat.

2. Pyramidella. Five species.

Shell smooth, not covered with epidermis, conical, elongated or sub-turriculated; aperture semi-oval, entire; the outer lip sharp, dentated interiorly, plaited, enlarged over the umbilicus, which it leaves more or less exposed.

P. dolabrata. The dentated Pyramidella. Pl. 22, fig. 5.

Answers to the above description; when placed on its base, it falls on one side.

P. terebellum. The wimble Pyramidella.

Smooth, glossy, white, with reddish-brown bands; columella recurved; inside of the lip smooth.

FAMILY XIV.
Scalarides. Three genera.

1. Vermetus. One species.

Resembling in appearance the shell of a Serpula; but the organization of the animal caused this to be made a distinct genus.

Its shells are usually found grouped together or intertwined with each other, and are very remarkable for being attached to marine bodies by the attenuated and pointed extremity of the spire.

Shell conical, tubular, thin, involute spirally, more or less close, with whorls almost completely disunited; free or adherent by intertwining; aperture straight, circular, with edges sharp and complete; several partitions not perforated towards the summit; operculum horny and complete.

V. lumbricales. The wormlike Vermetus. Pl. 23, fig. 3.

A flexuous shell, with a spiral, acute tip, very much resembling a corkscrew; colour reddish brown, sometimes clouded with a darker shade.

2. Scalaria. Seven species.

A marine shell, with a circular aperture like the Cyclostoma, but easily distinguished by its turreted form; longitudinal, elevated ribs, never connected together, rather oblique, and sharp; the shape of the shell is elegant, being a spiral cone, formed by gibbous whorls, unconnected by a columella, gradually increasing from the apex to the base. The colour is generally yellowish or brownish white. When perfect and of good size, they are of great value and highly prized.

Shell sub-turreted, the whorls of the spire more or less pressed and garnished with interrupted longitudinal ribs, formed by the successive preservation of the reflected margin of the aperture, which is small, perfectly round, with edges united, thickened, and outwardly reflected; operculum horny and thin.

S. pretiosa. The precious Scalaria, more commonly called the Wentle Trap, or Winding Staircase. Pl. 23, fig. 1.

This shell has its spiral whorls separate, and appears like an attenuated tube evolved round a cone; spire detached, with a deep umbilicus; volutions connected by longitudinal ribs; body extremely ventricose; colour cream yellow.

S. communis. The common Scalaria, or false Wentle Trap.

More taper and elongated than the S. pretiosa. It has no umbilicus, and the whorls are closely united.

3. Delphinula. Three species.

A marine shell, which, like the Scalaria, has a round aperture, but its solidity and pearly substance distinguishes it from the Cyclostoma, which is terrestrial.

Shell thick, pearly in the interior, sub-discoid or conical; the spiral whorls sometimes detached, rounded, spiny, with a large umbilicus; aperture round or multrigonal, not modified; edges perfectly united with a small spire, tuberculated exteriorly.

D. laciniata. The fringed Delphinula. Pl. 23, fig. 5.

Shell depressed, umbilicus large, surrounded by large vaulted scales in spiral rows; strong waved spiral striÆ; colour reddish purple, variegated with white.

FAMILY XV.
Turbinacea. Seven genera.

1. Solarium. Seven species.

Some shells of this genus are highly valued for their beauty and rarity.

Shell orbicular, involuted almost in the same plane; Planorbis-shaped; the spire of the right side very depressed; umbilicus large and conical, with edges denticulated or not at the entrance; aperture not modified by the last whorl of the spire, which is entirely flat; no columella.

S. perspectivum. The perspective Solarium. Pl. 23, fig. 4.

Species very carinated in their circumference; the aperture square; umbilicus large and crenated; colour yellowish, with brown and white bands on the sutures of the volutions.

S. variegatum. The variegated Solarium.

Species sub-carinated, aperture sub-orbicular.

2. Trochus. The Top Shell. Sixty-nine species.

This genus derived its name from its resemblance to a top.

The shells are marine, found in almost all parts of the world; some are smooth, but the greater number are covered, with knobs, spines, tuberculations, or undulations.

The long spines on the margin of the T. Solaris are placed at regular distances, and resemble the rays of the sun. Many, when decorticated, look like mother-of-pearl; others have a splendid metallic lustre. The T. agglutinans possesses the faculty of covering itself with extraneous substances, such as stones, corals, fragments of shells, &c. Of this species there are two kinds, which, though conchologically known only by one name, are familiarly known by two; the Conchologist and the Mineralogist; the former so called from being loaded with shells, and the latter with stones, &c. Sometimes the Conchologist is loaded with corals only, and then is called the Zoologist.

Shell thick, generally pearly, shaped like a top, spire sometimes depressed, sometimes elevated and pointed at the summit, sharp or carinated at its circumference, umbilicated or not; aperture depressed, angular or sub-angular, sometimes heart-shaped, with edges disunited; the right sharp; the columella arched, twisted, and often projecting forward; operculum horny, thin, with numerous spiral whorls, narrow, and increasing a little from the centre to the circumference.

T. imperialis. The imperial Trochus. Pl. 23, fig. 6.

Species umbilicated, spire very depressed, sharp and radiated at their circumference by the preservation of an angular canal from the middle of the right margin. This species is rare and beautiful, found in New-Zealand.

T. zizyphinus. The livid Trochus.

Species with strong transverse striÆ; colour livid, with undulated streaks of red or brownish carnation.

T. agglutinans. The agglutinating or Carrier Trochus.

Species umbilicated, with spire very depressed; the base much enlarged, and as if excavated by the large projection of the angle of the right edge, which advances much beyond the rounded columellar edge; generally covered with shells, stones, or coral.

T. niloticus. The large marble Trochus.

Species not umbilicated, conical, with base flat and circular; the columella twisted; the aperture very angular.

T. obeliscus. The obelisk Trochus.

Species not umbilicated, conic, elevated, flat and circular base; the termination of the columella strongly twisted, but passing down by the margin, appearing sloped by the advance of an internal longitudinal plait.

T. iris. The iris Trochus.

Species not umbilicated, conic, base oblique; aperture large, slightly angular; the columella twisted, and forming a kind of tooth at its termination.

T. granulatus. The granulated Trochus.

Conic, imperforate at the base, spirally granulated and not marginated at the edges of the volutions; body swelling out; spire tapering abruptly; apex acute, flesh-coloured.

T. umbilicaris. The umbilicated Trochus.

Shell conico-convex, rather flat, rounded at the top; apex depressed, volutions sub-marginate; striated spirally; aperture compressed and angular; umbilicus large, extending to the apex; colour whitish.

3. Monodonta. Twenty-three species.

This genus occupies an intermediate space between the Trochus and the Turbo; distinguished from the former by the aperture being more round and slightly depressed, and from the latter by the toothlike projecting angle which the truncated columella occasions at the base of the aperture.

Shell ovate or conoid, aperture round and entire, with an operculum; outer lip disunited from the body at the top; columella arched and truncated at the base.

M. coronaria. The crowned Monodonta.

Species in which the columella greatly projects, and the spire is entirely flat; covered with numerous small tubercles; colour white; the columella tinged with red.

M. labio. The double-lipped Monodonta. Pl. 23, fig. 2.

Species sub-globular, umbilicated, spiral whorls rounded; the columella terminated by a tooth.

M. fragarioides. The strawberry-shaped Monodonta.

Species more or less globular, of which the columella, almost straight, offers but a little obstacle to its junction with the margin.

4. Turbo. The Turban Shell. Thirty-four species.

Distinguished from the Monodonta by never having the columella truncated at the base; and from the Trochus by being solid, with the whorls constantly convex and never flattened. Like the Trochus, when decorticated, the Turbo exhibits splendid pearly, gold, or silver irridescent colours.

Shell thick, pearly in the interior; depressed, conical, or sub-turreted; umbilicated or not, little or not carinated at its circumference; aperture round or little depressed; the middle of the external edge not bent, but sometimes hollowed or sloped in some part; the edges rarely joined by a callosity; the columella arched, rarely twisted, and not truncated at the base; operculum calcareous or horny; the spire visible externally in the latter and interiorly in the former; the exterior often thickened and curved.

T. pica. The Magpie Turbo. Pl. 24, fig. 6.

Species in which the aperture is oblique; the columella losing itself entirely in its continuation with the margin, the umbilicus always uncovered; colour black and white.

T. setosus. The bristly Turbo.

Thick, transversely and deeply sulcated, longitudinally striated; spire short, volutions rounded, lip crenulated; inside pearly, variegated with white, green, and brown.

T. rugosus. The rough Turbo.

Species of which the aperture is perfectly round in the direction of the axis; the operculum horny.

5. Planaxis. Two species.

Shell marine, generally small, solid, of an oval conical form, oblong, a little sloping in front; columella flattened and truncated anteriorly; right margin furrowed or radiated within, and thickened by a callosity running to its origin; operculum oval, thin, horny, and sub-spiral.

P. sulcata. The furrowed Planaxis. Pl. 27, fig. 4.

Imperforate, furrowed transversely; outer lip crenulated and striated internally; colour grayish white, spotted with black, forming oblique longitudinal bands.

6. Phasianella. The Pheasant Snail. Ten species.

This genus of shells is celebrated for the beauty and variety of the colouring, disposed in such a manner as to resemble the plumage of a pheasant.

They are marine shells, many of which are rare and valuable; they possess a very distinctive character, that of a slightly projecting angle running along the columella.

Shell rather thick, oval, smooth, without epidermis, spire pointed; aperture oval, larger in front, with disunited edges; the right sharp; the columella uniting itself a little with the left edge, and offering interiorly a longitudinal callosity; operculum calcareous, oval, oblong, sub-spiral, the summit at one of its extremities.

P. picta. The painted Phasianella. Pl. 24, fig. 2.

Species smooth, oval, glossy, volutions inflated; reddish white, with crimson or reddish brown spots; aperture sub-ovate.

7. Turritella. The Screw Shell. Thirteen species.

This genus is easily distinguished from all screwlike shells by a sinus on the right margin of the aperture, not existing in any other shell of similar form.

Shell marine, turreted, not pearly, rather thin, striated according to the turning of the spire, which is very pointed, and has numerous whorls; aperture rounded; the edges disunited posteriorly; the right extremity thin, and, when perfect, having a light sinus about the middle; operculum horny.

T. bicingulata. The twice-girdled Turritella. Pl. 24, fig. 5.

Species that answers to the above description.

T. terebra. The auger Turritella.

Taper, pointed, acute transverse striÆ, the intermediate spaces prominent and acute; white, reddish, or cream coloured.

FAMILY XVI.
Canalifera. Eleven genera.

1. Cerithium. Thirty-six species.

A beautiful and numerous genus of turreted shells, with an expanded outer lip and short beak; the greater part are marine; many are found at the mouths of rivers, and a few in lakes, though none can properly be called river shells. In appearance they are like an elongated pyramidal cone, and the spire is at least two thirds the length of the shell. The exterior is seldom smooth, but striated, tuberculated, granulated, or spinous.

Shell more or less turreted, generally tuberculated; aperture small, oval, oblique; the columellar edge hollowed, callous; the right edge sharp, and dilating a little with age; operculum horny, oval, rounded, sub-spiral, and striated.

C. vertagus. The curved beak Cerithium. Pl. 24, fig. 3.

Species with evidently a small canal, very short, and recurved obliquely towards the back.

C. aluco. The caterpillar Cerithium.

Species with a canal much smaller, but entirely straight, and a sinus well formed at the posterior union of the two edges.

C. semigranosum. The semi-granulated Cerithium.

Fusiform, turreted; apex acute; the suture with double spiral rows of large granules; minutely striated transversely, with sulcated granulations; colour reddish brown.

2. Pleurotoma. Twenty-three species.

Distinguished from the Cerithium by having a notch or slit in the right margin.

Shell fusiform, rather rugged, spire turreted; aperture ovate, small, terminated by a canal variable in length; the right edge sharp, more or less notched; operculum horny.

P. Babylonia. The Tower of Babel Pleurotoma. Pl. 24, fig. 1.

Species in which the tube is rather long, and the notch is a little posterior to the middle of the edge.

P. auriculifera. The eared Pleurotoma.

Species in which the tube is short, and the notch entirely against the spire.

P. nodifera. The knotty or Javanese Pleurotoma.

Species with outer lip largely notched and deeply crenulated; upper volution smooth; under volution and body striated transversely, with angulated oblique nodules at the suture; colour reddish yellow.

3. Turbinella. Twenty-three species.

By LinnÆus this genus was classed with the Voluta, though they are more closely allied to the Murex; differing, however, from them by having no varices.

Shell generally turbinated, but sometimes turreted, rugged, and thick; spire variable in form; aperture elongated, terminated by a straight canal, often rather short; the left edge almost straight, and formed by a callosity which hides the columella; the right edge entire and sharp; the columella with two or three unequal, almost transverse plaits.

T. rapa. The turnip Turbinella.

Species fusiform and almost smooth.

T. scolymus. The artichoke Turbinella.

Species turbinated and spinous.

T. infundibulum. The funnel-shaped Turbinella.

Species turreted and fusiform.

T. pyrum. The pear-shaped Turbinella.

Species with spire short, mucronate; apex mammiliform, beak long; columella with four plaits; colour yellowish white, with irregular reddish brown spots.

4. Cancellaria. Twelve species.

This genus is not given by De Blainville precisely like Lamarck, as he has removed those that are greatly canaliculated either to the Murex or Turbinella. They are all marine shells, and greatly approximate the last-mentioned genus.

Shell oval, globular, ventricose, rugged; the spire middling, pointed; aperture ovate, enlarged, grooved, and sometimes sub-canaliculated anteriorly; the right edge effuse, concave, sharp; the left or columellar edge almost straight, and marked in the middle by two or three plaits; operculum horny.

C. reticulata. The reticulated Cancellaria. Pl. 25, fig. 5.

Oval, strong, ventricose; columella with three plaits; distant, coarse, reticulated striÆ; sometimes with yellow or orange bands; aperture white.

5. Fasciolaria. Eight species.

This genus was separated by Lamarck from the Murex of LinnÆus on account of having no varices.

Shell fusiform or sub-fusiform; aperture middling, elongated, almost symmetrical, terminated by a rather long straight tube; external edge sharp; the columellar edge with two or three oblique plaits.

F. tulipa. The tulip Fasciolaria. Pl. 25, fig. 4.

Species fusiform, not tuberculated.

F. trapezium. The striped tower Fasciolaria.

Species fusiform, volutions tuberculated, ventricose; reddish fawn coloured, with transverse double, slightly undulated lines; inside of aperture with reddish striÆ.

F. filamentosa. The threaded Fasciolaria.

Species turreted and tuberculated.

6. Fusus. Thirty-six species.

Likewise taken from the Murex; they are marine shells, of an elongated fusiform shape, with whorls ventricose in the middle or at the lower extremity.

Shell covered with epidermis, rough, fusiform, or ventricose in the middle; prolonged behind by the spire, but particularly forward by the canal; aperture oval; the columellar edge straight or nearly so; the exterior edge sharp; operculum oval, horny, with sub-concentric elements, and summit lateral.

F. colus. The spindle Fusus. Pl. 25, fig. 3.

Species turreted or sub-turreted, not umbilicated; outer lip entire, columella smooth.

F. filosus. The threaded Fusus.

Species sub-turreted and umbilicated.

7. Pyrula. Twenty-eight species.

Distinguished from the Fusus by having a short depressed spire, and the last whorl very large and ventricose, giving this shell the shape of a pear.

Shell pyriform by the depression of the spire, the canal conical, very long or middling, sometimes a little sloped; aperture oval, very large; columella smooth.

P. melongena. The open-mouth Pyrula. Pl. 25, fig. 6.

Species ventricose, tube or canal short; aperture very large and effuse; tuberculated, striated longitudinally.

P. ficus. The fig Pyrula.

Spire very short; volutions rounded above; very thin and ventricose; colour yellowish brown, with dark brown spots; covered with decussated striÆ.

8. Struthiolaria. Two species.

The shells of this genus are marine, inhabited by mollusca, that, by frequently moving in and out of the shell while wandering on the shore in search of food, produce singular callosities on the two edges of the aperture. They generally resemble the Murex and Buccinum, but are distinguished by a thickened marginal lip on the right side.

Shell ovate, spire produced; aperture sinuous, terminated at the base by a very short canal; straight, and without a notch; columellar edge callous and effuse; right edge with a thickened varix.

S. nodulosa. The nodulous Struthiolaria. Pl. 25, fig 1.

Ovate, grooved and striated transversely; top of volutions flattened and nodulous; cream-coloured, with undulated, brownish-yellow longitudinal lines; interior of lip yellowish.

This genus of shells has two rows of varices or thickened bands, arranged on either side in rows, so that it forms a distinct division between the Struthiolaria and the Murex.

Shell oval, as if depressed by the preservation of each side of a longitudinal thickened band; aperture oval, almost symmetrical by the excavation of the columellar edge, terminating anteriorly by a short canal, often a little sloping; a sinus at the posterior junction of the two edges.

R. ranina. The froglike Ranella. Pl. 25, fig. 2.

Species not umbilicated.

R. granulata. The granulated Ranella.

Species not umbilicated.

R. spinosa. The prickly Ranella.

Species of which the varices have elongated spines; beak sulcated; outer lip internally crenated; acute, short, distinct muricated tubercles; fawn coloured.

10. Murex. The Trumpet Shell. Sixty-six species.

Though so greatly divided by Lamarck, this is a beautiful and numerous genus, comprehending only such shells as have three or more varices on each whorl.

These varices show the number of times the animal has increased the size of its shell, and what proportion is added at each increase.

The shells are generally irregular in form, arising from their surfaces being usually armed with spines, knobs, striÆ, or foliations.

Shell generally oval; the spire always but little elevated, armed with longitudinal transverse varices or thickened bands; aperture small; very oval and symmetrical by the excavation of the left edge, formed by a plate applied on the columella, terminated anteriorly by a middling sized canal, sometimes very long and close; the right edge more or less adorned with varices; operculum horny, oval, complete, almost circular, with sub-concentric partitions; summit terminal.

M. crassispina. The thick-spined Murex. Pl. 26, fig. 3.

Species with tube very long and spiny.

M. adustus. The burnt Murex. Pl. 26, fig. 1.

Species with three ramified varices.

M. Haustellum. The Snipe Murex. Pl. 26, fig. 4.

Species with tube very long, and without spines.

M. acanthopterus. The prickly Murex.

Species with three varices on each whorl.

M. melanomathos. The black-spined Murex.

Species which have whorls with more than three varices; the tube almost close.

M. lyratus. The lyre-shaped Murex.

Species sub-turreted.

M. vitulinus. The young Murex.

Species sub-globular; the spire and the canal rather short, very open; the aperture sub-effuse.

11. Triton. Thirty-one species.

In this genus the varices are in longitudinal rows or series, but alternating, few in number, sometimes only one on each whorl. They are never spinous or foliated, though frequently plaited or tuberculated.

The Triton variegatus type of this genus is one of the largest spiral shells.

Shell oval, with spire and canal straight, middling, generally rough, garnished with varices, rare, scattered, and preserved in longitudinal rows; aperture sub-oval, elongated, terminated by a short, open canal; the columellar edge less hollowed than the right, and covered with a callosity; operculum horny, oval, rounded, and rather large.

T. variegatus. The trumpet Triton. Pl. 26, fig. 5.

The smoothest species, oblong, ventricose, tubiform; aperture dilated; suture of the spire crenulated; pillar lip grooved obliquely; colour pale purple, clouded and spotted with brown.

T. cutaceus. The rough-skin Triton.

Species with spire rather short, always very tuberculated, often umbilicated; a sinus at the posterior junction of the two edges.

T. anus. The grinning Triton.

Species similar to the T. cutaceus, but having the aperture surrounded by a thin dilated membrane and irregular teeth.

1. Rostellaria. Three species.

Lamarck formed this genus from the Strombus of LinnÆus on account of having a sinus in the lower part of the right margin contiguous to the canal. The beak is generally curved, and short in comparison to the length of the spire, but sometimes it is straight, and equal in length to the other part of the shell.

The R. rectirostris is one of the most rare shells known.

Shell sub-depressed, turreted, with spire produced and pointed; aperture oval by the excavation of the columellar edge; the right margin dilating by age, and having a sinus contiguous to the pointed canal which terminates the shell.

R. curvirostris. The curved beak Rostellaria. Pl. 27, fig. 2.

Species with the right edge digitated.

R. pes-Pelicani. The Pelican’s foot Rostellaria.

Species turreted, with four digitations on the right edge; body and volutions ribbed longitudinally and crowned with papillÆ; flesh-coloured or white.

2. Pteroceras. Seven species.

Formed from the Strombus, being distinct from it by not having the canal at the base shortened or truncated. It greatly resembles the Rostellaria, but the sinus of the right margin is distant from the body. From its digitation or long recurved claws it has often been called the Spider Shell.

Shell oblong-ovate, ventricose, canal elongated, attenuated, and often closed; right margin dilating by age into an expanded, digitated wing, attached to and covering a short spire, with a sinus in the lower part not contiguous to the body.

P. chiragra. The Devil’s Claw. Pl. 28, fig. 3.

Tuberculated, with six digitated, canaliculated rays, closed in the adult shell; outer lip internally striated.

P. scorpio. The Scorpion Pteroceras.

Species with digitations on the external edge, varying in number from six to ten.

3. Strombus. The Wing Shell. Thirty-two species.

As now defined and characterized by Lamarck, is easily distinguished by not having the winged aperture on the right side dentated or digitated, and the sinus therein always separated from the canal.

In some species the exterior is variously striated, smooth, wrinkled longitudinally, or tuberculated; the interior presents vivid and beautiful colours.

These shells frequently attain a large size and great solidity.

Shell thick, sub-involute, diconic, or ventricose, terminated like a cone before and behind; aperture very long, narrow, terminated anteriorly by a canal more or less elongated, recurved; the edges parallel; the external dilating with age, offering behind a gutter at its attachment to the spire, and before a sinus more posterior than the canal, through which passes the head of the animal; operculum horny, long, and narrow, with elements as if imbricated; the summit terminal.

S. polyfasciatus. The many-banded Strombus. Pl. 28, fig. 2.

Species distinguished by its bands, and by having the margin of the outer lip thickened.

S. auris-DianÆ. Diana’s Ear Strombus.

Oblong-ovate; spire acute, tuberculated, and transversely striated; base recurved, outer lip thick, anterior lobe with a finger-like termination.

S. pugilis. The fighting, or thick-spined Strombus.

Anterior lip prominent, rounded, smooth; spire crowned with spines, the outermost whorl cancellate; columella much reflected; beak three-lobed, obtuse, flesh-coloured, and polished within.

FAMILY XVIII.
Purpurifera. Eleven genera.

1. Cassidaria. Five species.

Marine shell, sometimes confounded with the Cassis, but distinguished by the canal which terminates the aperture being ascendant, very little arched, and not suddenly recurved.

Shell sub-globular, ventricose, tuberculated, or fluted; spire short and pointed; aperture long, oval, sub-canaliculated anteriorly; the right edge effuse and folded back; the columella covered over with a broad, smooth callosity, uniting behind to the right edge; operculum horny.

C. echinophora. The tuberculated Cassidaria. Pl. 27, fig. 5.

Species oval, sub-globular, canal sub-ascendant, with tuberculated belts or ribs.

C. Tyrrhena. The Tyrrhenian Cassidaria.

Species ovate, grooved transversely, volutions convex; apex with one tubercle; tawny colour.

2. Cassis. The Helmet Shell. Twenty-five species.

This genus was formed from the Buccinum, from which it is easily distinguished; the latter having only a notch at the base, and the Cassis with a canal abruptly turned towards the back of the shell.

Shell inflated oval, sub-involute, spire very little projecting; aperture long, oval, sometimes very narrow, terminated anteriorly by a very short canal, sloped and recurved obliquely towards the back; the right edge more or less concave, reflected backward, and often dentated within; the columella covered with a large callosity, denticulated or wrinkled in all its length; operculum horny.

C. tuberosa. The tuberous Cassis. Pl. 28, fig. 5.

Species in which the aperture is long, the external edge almost straight, and the spire with thickened bands.

C. flammea. The flaming Cassis.

Species in which the aperture is sub-oval, and the external edge excavated; spire short, base triangular; columella rugose; outer lip thickened.

C. areola. The draught-board Cassis.

Smooth, shiny, white, with square orange tesselated spots; spire short and conical, with decussated striÆ; lower part of columella rugose.

3. Ricinula. Nine species.

Shell oval or sub-globular, thick, armed with points or tubercles, with a depressed spire; aperture narrow, elongated, notched, sometimes canaliculated anteriorly, and digitated externally; the left edge more or less callous, sometimes denticulated; operculum horny, oval, transverse, with elements slightly imbricated.

R. horrida. The horrid Ricinula. Pl. 26, fig. 2.

Species without a canal; exterior covered with strong, obtuse black tubercles, with the interstices white, striated transversely; interior rich purple colour; outer lip with five triangular grooved radii, between which at their base the margin is crenulated.

R. digitata. The digitated Ricinula.

Species canaliculated; two long palmated digits at the side of the aperture.

4. Purpura. Fifty species.

This genus has its name from the purple liquid produced by the animal, from which the ancients extracted the Tyrian purple dye. This is the last genus that presents the appearance of a canal at the base of the aperture, and therefore rightly precedes the remaining genera of this family, all of which are without a canal.

Shell oval, thick, generally tuberculated; spire short; the last whorl much greater than all the others united; aperture oval, greatly dilated, terminated anteriorly by a canal short, oblique, and notched at the extremity; the columellar edge almost straight, covered with a callosity pointed anteriorly; operculum horny, flat, almost semicircular, with transverse striÆ slightly marked; the summit behind.

P. Persica. The Persian Purpura. Pl. 28, fig. 4.

Transversely sulcated and striated between the ridges; colour burnt-umber, ridges yellowish, with dark brown spots; upper ridge and the superior edges of the volutions mucronate; interior sulcated and striated.

P. lapillus. The common Purpura.

Species small, white, sometimes banded with yellow or brown, with a scaly surface.

5. Monoceros. The Unicorn. Five species.

Derived its name from the long, conical-pointed, somewhat recurved tooth in the outer lip, by which alone it can well be distinguished from the Purpura; and with this characteristic difference the description of the shell of the Purpura will answer for this genus.

M. cingulatum. The belted Monoceras.

Cylindrical, columella not smooth, but irregularly plaited or wrinkled, and the tooth does not extend within the interior of the whorls as in the other species, but appears affixed only to the edge of the lip; volutions flattened in their upper edges; transverse spiral brown bands.

6. Concholepas. One species.

Formerly considered a Patella, but distinct from it on account of having an operculum. It is particularly distinguished by having two teeth at the base of the right side.

Shell wide, rough, oval, spire very short, not projecting; aperture very large, oval, effuse, sloped anteriorly; the edges united; the right or external very thick, dentated; the two teeth which limit the slope are a little larger than the others; muscular impression visible, and almost in form of a horseshoe; operculum horny and rudimentary.

C. Peruvianus. The Peruvian Concholepas. Pl. 28, fig. 1.

The type of this genus; exterior dark brown, interior white.

7. Harpa. The Harp Shell. Eight species.

This genus of shells is truly beautiful; it was classed by LinnÆus with the Buccinum, but Lamarck considered that they were, for their beauty, worthy of forming a genus by themselves.

Shell oval, inflated, rather thin, with longitudinal parallel ribs, formed by the preservation of the thickening of the right margin; the spire very short, pointed, the last whorl much longer than all the others together; aperture large, ovate, widely notched anteriorly; the right edge much excavated and thickened outwardly; the columella smooth, and terminated in a point anteriorly.

H. imperialis. The imperial Harp.

Species in which the number of ribs far exceeds that of any other, and occasions it often to be called the many-ridged harp; a small spiral keel round the summit. A rare and valuable species.

H. nobilis. The noble Harp. Pl. 29, fig. 2.

A regular species.

H. rosea. The roseate Harp.

Oblong-ovate; flesh coloured, with roseate interrupted bands; ribs remote; columella of a fine rosy hue.

8. Dolium. The Tun Shell. Seven species.

The shells of this genus are generally large, thin, and globose, with a wide aperture, and toothed or crenated outer lip; they have a brittle and light structure, and although some of them grow to a very large size, they retain their characteristic fragility and thinness.

Shell sub-globular, very ventricose, thin, encircled by decurrent flutings; the spire very short; the last turn much larger than all the others together; aperture oblong, very large, by the great excavation of the right edge, which is crenated through all its length; columella twisted; operculum unknown.

D. perdix. The Partridge Dolium. Pl. 29, fig. 4.

Species sub-umbilicated, ovate-oblong, thin, thickly ribbed, and convex; colour reddish brown, clouded and spotted with white.

D. galea. The brown Tun.

Species not umbilicated; sometimes exceeds ten inches in diameter.

9. Buccinum. The Whelk. Fifty-eight species.

Notwithstanding the divisions of the LinnÆan Buccinum into so many different genera, it still presents a great variety and diversity of species.

Shell slightly covered with epidermis, oval, elongated; the spire middling elevated; aperture oblong, oval, notched, and sometimes sub-canaliculated anteriorly; the right edge thick, not reflected; columella simple and swelled at the upper part; operculum horny, complete, oval, with sub-concentric elements; the summit slightly marked and marginal.

B. undatum. The common Whelk, or waved Buccinum.

Species oval, slightly ventricose, and sub-carinated on the whorls of the spire; sulcated obliquely; striated transversely and longitudinally; volutions convex; aperture white or yellow; covered with a yellowish epidermis.

B. papillosum. The prickly-lip Buccinum. Pl. 29, fig. 1.

Species with the spire elevated, more or less tuberculated, the edges of the aperture separated posteriorly by a narrow, rather deep sinus; the right dentated anteriorly.

B. reticulatum. The reticulated Buccinum.

Species short, ventricose, sub-globular.

B. achatinum. The Agathine Buccinum.

Species smooth, the spire rather elevated; the aperture wider anteriorly.

10. Eburna. Five species.

Shell oval or elongated, smooth; the spire pointed, its whorls as if rounded; aperture ovate, elongated, effuse, and widely notched anteriorly; the right margin entire; the columella callous posteriorly, umbilicated, sub-canaliculated at its external or right side.

E. Ceylanica. The Ceylon Eburna. Pl. 29, fig. 3.

Species smooth, white, with irregular large purplish spots; apex acute, tipped with blue; sutures with an elevated line; umbilicus filled with spines.

11. Terebra. The Needle Shell. Twenty-four species.

This genus of shells is remarkable for their sharp, lengthened, and spiral form, which obtained for them the common name of Needles.

Shell elongated oval, spire pointed, slightly elevated, or sub-turreted; aperture wide, oval, strongly notched anteriorly; lower end of the columella twisted or oblique.

T. Buccinoides. The Buccinum-shaped Terebra. Pl. 27, fig. 3.

Answers to the above description.

T. vittata. The filleted Terebra.

Species smooth, pale fawn coloured; transversely striated, with transverse purplish fillets.

T. maculata. The spotted Terebra. Pl. 27, fig. 1.

Species very long, spire pointed; aperture oval, small, widely notched anteriorly; the external edge thin and sharp, the left with an oblique thickening at its extremity.

FAMILY XIX.
Columellaria. Five genera.

1. Columbella. Eighteen species.

The shells of this genus are short, small, and rather thick; found in the seas of hot countries.

The C. mercatoria is very common on the shores of the Atlantic in warm latitudes, and was formerly used as money.

Shell thick, turbinated; spire short, obtuse; aperture narrow, elongated, terminated by a very short canal or notch, rendered narrow by an inflation at the inner side of the right edge, and by some plaits on the columella; a very small horny operculum.

C. strombiformis. The Strombus-shaped Columbella. Pl. 29, fig. 6.

The type of this genus, partly characterized by its name.

C. mercatoria. The merchant Columbella.

Ovate, white, sulcated, transversely clouded with brown or yellow; outer lip dentated internally.

2. Mitra. The Mitre Shell. Eighty species.

A numerous and elegant genus of shells, separated by Lamarck from the Voluta on account of possessing several strong distinctive characters. The spire is always pointed, and the columellar plaits, diminishing in size, are always transverse and parallel to each other.

The exterior is sometimes most beautifully marked with transverse grooves, striÆ, punctures, or granulations; the colour of almost every hue.

Shell turreted, sub-fusiform, and oval; the spire always pointed at the summit; the aperture small, triangular, wider and strongly notched anteriorly; the external edge sharp, almost straight, always longer than the columella, which is formed by a very thin callosity, and marked with oblique parallel plaits, of which those anterior are the shortest.

M. episcopalis. The episcopal Mitre. Pl. 31, fig. 7.

Species turreted, with spiral whorls very wide and entire; the aperture effuse anteriorly.

M. papalis. The papal Mitre.

Species with coronated whorls.

M. pontificalis. The pontifical Mitre.

Species covered with a yellowish epidermis, beneath which are interrupted fillets of orange coloured spots; spire crowned with tubercles.

M. micozonias. The small white-banded Mitre.

Species sub-ovate, spire very short, generally tubercled.

M. dactylus. The six-plaited Mitre.

Species oval, spire very short, and generally latticed.

M. tÆniata. The riband Mitre.

Species flaring, turreted, ribbed; spire more than half the length of the shell; aperture very narrow, long, sub-canaliculated, with one plait.

3. Voluta. The Volute or Wreath. 44 species.

This genus, as established by LinnÆus, included shells of different families, promiscuously blended together, rendering it difficult to determine satisfactorily respecting shells under examination. As arranged and classified by Lamarck, it is still a numerous and beautiful genus, containing some of the most rare and costly shells, particularly V. Junonia or Peacock Volute, of which very few are known. They vary considerably in size; some are very minute, and others large; they are found chiefly in the seas of the torrid zone or southern hemisphere.

Shell oval, more or less ventricose; the first whorls of the spire mamillose; aperture in general much more long than wide, strongly and obliquely notched anteriorly; the right edge a little reflected, entire; the columellar edge excavated, and adorned with great plaits, more or less oblique, and a little variable in number with age.

V. Æthiopica. The Æthiopian Volute. Pl. 30, fig. 2.

Species large, oval, convex, ventricose; spire papillary, with whorls coronated with elevated hollow spines.

V. musica. The music Volute.

Species oval, marked like musical notes set in scores on its surface; spire sub-tuberculated.

V. Magellanica. The Magellan Volute.

Species sub-fusiform, elongated, and sub-turreted; no spines or tubercles on the whorls.

4. Marginella. Twenty-four species.

Distinguished from the Voluta, from which it was taken, by having the outer lip thickened.

Shell smooth, polished, ovate, oblong, sub-conic, spire short and papillary; aperture narrow, sub-ovate, by a light curve of the right edge, which is inflated or reflected, slightly notched anteriorly; the columellar edge marked with three distinct oblique plaits.

M. lineata. The lineated Marginella. Pl. 30, fig. 3.

Species with aperture as long as the shell; spire not projecting, sometimes sunk or umbilicated.

M. faba. The Bean Marginella.

Species with aperture shorter than the shell, and the spire projecting.

M. cÆrulescens. The cerulean Marginella.

Species with surface bluish white; spire short and acute; four plaits on the columella; interior lip brownish purple.

5. Volvaria. Five species.

The connecting genus between those shells that have a columella and those that are evolved upon their own axis. Distinguished from the Marginella by not having a thickened outer lip. The shells are marine, and generally very small.

Shell cylindrical, convolute; spire obsolete or concealed; aperture narrow, the whole length of the shell, with one or more plaits on the columella at the lower part.

V. monilis. The Necklace Volvaria. Pl. 29, fig. 5.

Species greatly involuted; aperture very narrow and very long; plaits on the anterior part of the columellar edge; the exterior edge thin.

FAMILY XX.
Convoluta. Six genera.

1. Ovula. The Egg. 12 species.

This is the first genus of Lamarck’s arrangement of convoluted shells; it is nearly allied to the CyprÆa, but easily distinguished from it by the want of spire, and by not having teeth on the columellar lip; the right lip is reflected inwardly, sometimes wrinkled and sometimes smooth.

Shell oblong, convex, resembling the CyprÆa in form, with the two extremities of the aperture notched, and more or less prolonged like a tube; the left margin dentated.

O. volva. The Weaver’s Shuttle. Pl. 34, fig. 4.

Species in which the right edge is not thickened or dentated, and with each extremity elongated, producing a long, straight tube, which increases with age. One of the most rare shells of this genus.

O. oviformis. The egg-shaped Ovula. Pl. 34, fig. 1.

Species ovate, much inflated, ventricose in the centre, very glossy and white; right edge dentated, the tube of each extremity very prominent; interior of aperture reddish purple.

O. gibbosa. The belted Ovula. Pl. 34, fig. 2.

Species gibbous, neither end dentated; tubes little marked, and with the body of the shell encircled by a blunt keel.

O. verrucosa. The warty Ovula. Pl. 34, fig. 3.

Species in which the right end is dentated, with a notch and a knob above at each extremity.

This genus derived its name from the Cyprian goddess, on account of the beauty of its polished shells. They are generally smooth, of great brilliancy of colour, and elegantly marked with dots, zigzag lines, undulations, or stripes, and covered with an enamel-like glaze. They are found buried in the sand at the bottom of the sea, and are covered by the animal with a thin membrane, which preserves the polish and prevents other testaceous bodies from adhering to them. This membrane consists of two parts, and arises on both sides of the shell in the form of wings, furnishing the testaceous and colouring matter; in some species they do not quite meet on the back of the shell, and the uncovered space is marked by a coloured dorsal line; when these membranous wings overlap each other, this line is nearly obsolete.

These shells often differ much with age; at first in thickness, then because the edges are thin, sharp, hardly dentated, unless internally; and, lastly, sometimes in the outline; this is because the two lobes of the mantle, by turning over the primitive shell during the creeping of the animal, deposite new calcareous matter. De Blainville cannot admit the hypothesis of Bruguiere, that these animals can completely abandon their shell to form a new one.

Shell, when full grown and mature, is solid, oval, convex, very smooth, involute; the spire entirely posterior, very small, often concealed by a calcareous layer deposited by the lobes of the mantle, leaving in some species a small cavity like an umbilicus; aperture longitudinal, very narrow, slightly curved, as long as the shell, with edges internally dentated, and notched at each extremity.

Shell, when young and immature, is very thin, the edges of the aperture not dentated; the right margin sharp and not reflected.

C. exanthema. The measly CyprÆa.

Species oblong-ovate, brown, with round white spots; dorsal line grayish; marginal teeth brown; spire not quite concealed.

C. Pantherina. The Panther CyprÆa. Pl. 31, fig. 4.

Species regular, beautifully spotted like a panther.

3. Terebellum. One species.

Shell convolute, thin, shining, sub-cylindrical, pointed behind, truncated before; aperture longitudinal, edges entire, columella truncated.

T. subulatum. The awl-shaped Terebellum. Pl. 31, fig. 3.

Answers to the above description, being the only living species known.

4. Ancillaria. Four species.

An intermediate genus between the Terebellum and the Oliva; distinguished from the former by a callous oblique band at the base of the columella; and from the latter by not having the spiral whorls separated by a groove.

Shell smooth, oval, oblong, pointed behind, enlarged and truncated before; the columella covered anteriorly by a callous oblique band; the right lip obtuse.

A. cinnamomea. The cinnamon Ancillaria. Pl. 30, fig. 5.

Species with spire nearly obsolete; shell chestnut colour, with white bands; varix of the columella reddish and somewhat striated.

5. Oliva. The Olive. Sixty-two species.

An oval, involuted, internal shell, distinguished from the Ancillaria by a narrow canal continued from its upper angle around the sutures of the spiral whorls. It was formerly classed with the Voluta, which genus has not the canal, so that they cannot be mistaken for each other. There is a callosity uniting with the spiral canal, and another at the base of the columella.

Shell thick, solid, smooth, oval, elongated, sub-cylindrical; the spiral whorls very small, separated by a canal; aperture long, narrow; the columellar edge reflected anteriorly by a callosity, and striated obliquely through all its length. The shells are generally clouded or covered with waved lines of a brownish colour, more or less dark.

O. subulata. The awl-shaped Olive. Pl. 30, fig 1.

Species elongated, with very projecting spire.

O. undata. The waved Olive. Pl. 30, fig. 4.

Species oval, spire hardly projecting.

O. cruenta. The bloody Olive.

Species cylindrical, suture canal deep; fawn colour, with triangular spots of purple, and two dark brown spots on the edge of the outer lip.

6. Conus. The Cone. One hundred and eighty-one species.

A genus valued on account of the beauty, symmetry, and variety of its species; some of its shells are very rare and remarkable for their richness of colouring; some are coronated, and others have a plain spire. They are all covered with an epidermis, beneath which is generally a smooth surface, with sometimes a high polish; a few are granulated and tuberculated. They are found in great abundance in the seas of warm climates.

Shell conic, covered with a membranous periosteum, thick, solid, involuted; the summit of the cone anterior; the spire little or not at all projecting; aperture longitudinal, very narrow, turning towards its anterior extremity; the external edge straight, with oblique plaits in its anterior part; operculum very small and horny, sub-spiral, with summit terminal.

C. textilis. The embroidered Cone. Pl. 31, fig. 2.

Species ovate, slightly elongated; the spire rather projecting, pointed, not coronated.

C. imperialis. The imperial Cone.

Species conic, spire coronated, projecting, or flat.

C. striatus. The striated Cone.

Species oblong-ovate, gibbous, not coronated, clouded and strongly striated transversely.

C. generalis. The general Cone.

Species conic, spire projecting, not crowned with tubercles; colour reddish brown, or clouded with orange and interrupted fillets.

C. mustelinus. The Weasel Cone. Pl. 31, fig. 1.

Species with base sub-truncated; spire channelled and banded with orange spots; body whitish, encircled in the middle by orange-spotted bands.

FAMILY XXI.
Nautilacea. Two genera.

1. Spirula. One species.

An involute, symmetrical, discoid shell, whose whorls do not touch each other; the septa or partitions are brilliant pearl, concave externally, pierced by a tube called the siphon or siphuncle, placed close to the inner edge of the aperture; covered with a thin epidermis.

S. Peronii. Peron’s Spirula. Pl. 36, fig. 2.

Answers to the above description; colour yellowish white.

2. Nautilus. Two species.

An elegant, well-known shell, more or less ventricose, discoid, slightly compressed, umbilicated or not, but never papillose; the septa simple, transverse, not visible externally, the last deeply sunk and perforated by a siphon running through them all; edges entire.

The N. Pompilius, when dissected, displays its beautiful pearly chambers; fine specimens are often converted into drinking-cups by the Orientals, who sometimes remove the outer coating, so that its whole appearance is pearly.

The Nautilis varies in size; some are microscopic; and although they have received different names, and on account of the animal have been made to form different genera, it was deemed unnecessary to treat of them here.

N. Pompilius. The Pompilius Nautilus. Pl. 36, fig. 3.

Species not umbilicated; the back rounded; aperture round and pearly; siphon sub-central; pale yellow, with chestnut streaks and undulations.

N. umbilicatus. The umbilicated Pompilius. Pl. 36, fig. 1.

Species umbilicated, sub-orbicular; pale fawn colour, with chestnut undated transverse clouds.

FAMILY XXII.
Heteropoda. Two genera.

1. Argonauta. The Paper Sailor. Three species.

The shells of this genus are remarkable for their fragility, delicacy, and elegance; they resemble a scroll, ornamented with various canaliculated grooves from the summit to the margin, which is bicarinated. The colour is usually bluish, but the keel is of a darker hue; they vary greatly in size.

Shell navicular, symmetrical, very thin, compressed, bicarinated, sub-involuted longitudinally in the same plane; aperture very large, entire, symmetrical, square in front, slightly modified by the turn of the summit, and provided on each side with an earlike appendage, with thick and smooth edges; lips sharp.

A. argo. The Portuguese man-of-war. Pl. 35, fig. 1.

Characterized above; shell whitish, fragile, keel rather narrow, with sharp-pointed tuberculations; sides striated transversely, wrinkled longitudinally.

A. tuberculosa. The tuberculated Argonaut. Pl. 35, fig. 2.

Species more convex at the sides, with nodulous elevations; keel broader, points more obtuse.

2. Carinaria. The glassy Nautilus. Three species.

In form and texture greatly resembling the Argonauta, but distinguished by only having one keel on the whole length of the back.

Shell symmetrical, carinated or not, very thin, slightly compressed, without spire, but with the summit slightly recurved posteriorly; aperture oval and very entire.

C. vitrea. The glassy Carinaria.

Species very rare and beautiful, thin, papyraceous, very fragile and semitransparent; a serrated keel rises up its front, and the sides are decorated with ribs parallel to the base.

C. fragilis. The fragile Carinaria.

Species smaller, very thin, striated longitudinally, diverging from the summit to the margin; no keel.

C. cymbium. The minute Carinaria.

Species not larger than a grain of sand.