A. piscatorium.

2. Siliquaria. Four species.

Shell very thin, conical, tubular, involuted in a loose and irregular spiral manner; aperture circular, edges sharp, interrupted in the middle by a notch prolonged like a slit through nearly all its length, stopped abruptly at some distance from the summit.

S. anguina. The Snake Siliquaria. Pl. 33, fig. 4.

Shell tapering, undulating, spiral at the extremity.

S. muricata. The Prickly Siliquaria.

Species armed with short spines or prickles; aperture sometimes margined; usually of a rosy or pink colour.

1. Clymene. One species.

C. amphistoma. The double-mouthed Clymene.

Tube thin and slender, open at both ends; incrusted externally with sand and fragments of shells.

2. Dentalium. The Tooth Shell. Twelve species.

This genus took its name from its resemblance to an elephant’s tooth. It is an attenuated conical tube, slightly bent, and open at both ends.

Shell tubular, regular, symmetrical, lightly curved longitudinally, conic, attenuated insensibly posteriorly, and open at each extremity by a round orifice.

D. elephantinum. The Elephant’s Tooth Shell.

Species in which the tube is striated or ribbed longitudinally; the ribs are generally ten in number; green colour.

D. entale. The common Dentalium. Pl. 33, fig. 1.

Species very minutely striated; white or yellowish colour.

D. pellucidum. The pellucid Dentalium.

Species narrow and thin; pale topaz colour.

D. politum. The ring-striated Tooth Shell.

Species finely pointed, solid, striated annularly; generally rosy or pink colour.

D. rectum. The straight Tooth Shell.

Species entirely straight, with longitudinal ribs.

D. eburneum. The Ivory Tooth Shell.

Species of a reddish or pale yellow colour, with the tip frequently tinged with orange or pink.

FAMILY III.
AmphitritÆa. Four genera.

The similarity of the four genera comprising this family is such, that it was thought sufficient to give only one type (the sabellaria crassissima), as the student may easily recognise the others.

1. Pectinaria. Two species.

A membranous or papyraceous tube, in the form of a reversed cone; unfixed; exterior covered with sandy adhesions.

P. Belgica. The Belgic Pectinaria.

Tube inversely conic, membranous, and covered with sand.

2. Sabellaria. Two species.

The covering of the animal belonging to this genus is composed of fragments and particles of marine substances, adhering to a tubular membrane; some are detached and others are fixed. The tubes are cellular at the base, and the orifice expanded.

S. alveolata. The Honeycomb Sabellaria.

Consists of numerous parallel tubes, nearly straight, communicating by an aperture, forming when in mass the appearance of a honeycomb; it adheres to rocks in clusters.

S. crassissima. The very thick or strong Sabellaria. Pl. 33, fig. 2.

Species incrusted with small stones; sometimes found thick and of a large size.

Tube elongated, cylindrical, membranous, attenuated and pointed at the base, with adhesions of sand.

T. conchilega. The shelly Terebella.

Tube covered with numerous fragments of broken shells.

4. Amphitrite. Six species.

Nearly the same as the Terebella, but of a tougher membranous texture, and generally without adhesions.

A. ventilabrum. The Fan Amphitrite.

Tube subulate, smooth, of a yellowish colour.

FAMILY IV.
Serpulacea. Five genera.

1. Spirorbis. Five species.

Tube testaceous, spirally twisted on a horizontal plane, with terminal aperture rounded or angular, attached by the lower part to marine substances.

S. Nautiloides. The Nautilus-shaped Spirorbis.

White, transversely wrinkled and minute.

2. Serpula. The Worm Shell. Twenty-six species.

The name of this genus is derived from the Latin word serpo, to creep, on account of the vermiform character of some of its species.

They are invariably tubular, sometimes solitary, but more frequently in clusters spirally entwined, adhering to marine substances. In colour they are brown, purple, yellow, tawny, pink or white, and sometimes tinged with green.

Tube solid, calcareous, irregularly twisted, fixed to other substances.

S. vermicularis. The wormlike Serpula.

White, cylindrical, tapering, rugged, variously curved and twisted.

3. Vermilia. Eight species.

Tube testaceous, cylindrical, more or less twisted, gradually attenuated posteriorly; opening round, the margin with one, two, or three teeth; shell adhering by the side to other substances; provided with a convex operculum.

V. triquetra. The three-sided Vermilia.

White or reddish, rugged, twisted and triangular, carinated along the back.

Distinguished from the Vermilia by a very peculiar operculum. Found in groups, adhering together at the base.

Tube open at the summit; aperture orbicular, terminated on the side by a spatulous tongue; operculum orbicular, squamose, consisting of from five to nine testaceous parts or valves, all attached to one side of the operculum; the middle one dentated at the truncated part of its summit, the others a little toothed on their internal edge.

G. elongata. The elongated Galeolaria.

Whitish, existing in congregated masses; operculum as above.

5. Magilus. One species.

A very singular shell, greatly resembling a petrified body, composed of a testaceous white substance like alabaster. The base is bent into a short spire, with about four contiguous whorls; the last prolonged and nearly straight. The animal, as it increases in size, abandons the spiral part by increasing the tubular part, filling up the part it quits with calcareous matter, which proves that it advances gradually.

Tube partially involuted, convex in its upper exterior part, the lower side flattened, platted, carinated, and somewhat angular; the spire short, helix-formed, and prolonged through the rest of its extent in nearly a right line; aperture entire, oval, with a sort of sinus or gutter in the middle line, producing the keel of the shell.

M. antiquus. The antiquated Magilus.

Answers to the above description; colour pale yellowish brown, transversely wrinkled.