FOSSIL SEA-LILIES, STARFISHES, BRITTLE-STARS AND SEA-URCHINS.

Divisions of Echinodermata.—

The sub-kingdom of ECHINODERMATA includes the above groups comprised in the Classes Crinoidea, Asteroidea, Ophiuroidea and Echinoidea. Besides these are the less important classes of the Cystidea or sac-shaped echinoderms (of which no definite remains are recorded from Australian rocks); the Blastoidea or bud-shaped echinoderms (of which four genera are known from Australia); the Edrioasteroidea or sessile starfishes (unknown in Australia); and the Holothuroidea or sea-cucumbers (represented as fossils by the skin spicules and plates, an example of which has been recorded from Australia).

CRINOIDEA, or Sea-lilies.

Crinoidea, their General Structure.—

These often beautiful and graceful animals resemble a starfish mounted on a stalk. They are composed of calcareous joints and plates, and are therefore important as rock-formers. The stalk or column may be either short or long, and is generally rooted, in the adult stage, in the mud of the sea-floor. Fossil Crinoids were sometimes furnished with a coiled termination, which could be entwined around such objects as the stems of sea-weeds. The crinoid column is composed of numerous plates, and is round or pentagonal. Upon this is fixed the calyx or cup, with its attached arms, which serve to bring food to the mouth, situated on the upper part of the cup. The arms are grooved, and the water, being charged with food particles (animalcula), pours down these channels into the mouth. The stem elevates the animal above the mud or silt of the sea-floor, thus making it more easy for it to obtain its food supply. The stalks of fossil Crinoids sometimes reached the enormous length of 50 feet. Their calcareous skeleton is built upon a plan having five planes of symmetry; this pentamerism is found throughout the crinoids, the blastoids and the free-moving echinoderma. Crinoids range from moderately shallow- to deep-water, and at the present day are almost restricted to abyssal conditions. The more ancient types usually found their habitats amongst reefs or in comparatively clear water, where there was a marked freedom from sediment, although that was not an essential, as seen by their numerous remains in the Australian mudstones and sandstones.

Cambrian Crinoids.—

The group of the Crinoidea first appears in the Upper Cambrian, and persists to the present time. In North America the genus Dendrocrinus occurs in the Cambrian and Ordovician; and some stem-joints from the Upper Cambrian limestone of the Mount Wellington district, Victoria, may be provisionally referred to this genus.

Ordovician Crinoids.—

No undoubted Crinoid remains have been found in the Australian Ordovician; although many genera are found elsewhere in that system, chiefly in N. America, as Reteocrinus, Hybocrinus, Heterocrinus and Dendrocrinus, and in Europe and North America, as Rhodocrinus and Taxocrinus.

Silurian Crinoids.—

The Silurian Crinoidea of Australia are largely represented by the remains of the columns or stalks, which are often found in such abundance as to constitute large masses of sub-crystalline limestone, as that of Toongabbie, Victoria. The columns of the Crinoids do not usually possess sufficient characters to enable the forms to be identified. There are, however, more perfect and identifiable remains of several very interesting generic types in the Silurian faunas as follows:—

In New South Wales Pisocrinus is represented with some reservation by (?) P. yassensis, found at Limestone Creek, near Yass (Fig. 76 A, B).

In Victoria, Helicocrinus plumosus and Botryocrinus longibrachiatus occur at Brunswick and Flemington, respectively (Fig. 76). The former is a delicate and handsome species, having a small cup with finely pinnate arms, which are forked once, and with a pentagonal stem coiled at the distal end (see Frontispiece). The genus Botryocrinus is found in rocks of a similar age in North America and England. Hapalocrinus victoriae, a member of the Platycrinidae, has been described from the mudstone of South Yarra, near Melbourne. The species above mentioned are of Melbournian age, belonging to the lower stage of the Silurian system.

Devonian Crinoids.—

In the Middle Devonian of Queensland, fragmentary crinoid stems are found interbedded with the limestone of the Broken River.

Thin slices of the limestone of the same age from Buchan, Victoria, show numerous ossicles and stem-joints of Crinoids.

Similar remains have also been recorded from the Devonian of the Kimberley district and the Gascoyne River in Western Australia.

Carboniferous Crinoids.—

The Carboniferous (Star Beds) of Queensland has yielded remains of Actinocrinus.

The Matai Series of New Zealand, which may be regarded as almost certainly of Carboniferous age, contains remains of a Cyathocrinus, found in the limestone of the Wairoa Gorge.

Carbopermian Crinoids.—

The Carbopermian (Upper Marine Series) of New South Wales yields the interesting Crinoid having a large, globular cup, known as Phialocrinus; the best known species of this genus are P. konincki (Fig. 76 E) and P. princeps. Beds of the same age in New South Wales, also in the Upper Marine Series, contain the aberrant Crinoid with strongly sculptured plates of the calyx in the decorticated condition, Tribrachiocrinus clarkei.

Poteriocrinus and Platycrinus are, with some reservation, recorded from the Gympie Series at Stanwell and the marine beds of the Bowen River Coal-field respectively, both in Queensland.

In Western Australia the Carbopermian rocks of the Gascoyne River are known to contain crinoid stems, tentatively referred to either the Rhodocrinidae or the Actinocrinidae. There is also a species of Platycrinus known from the Gascoyne and Irwin Rivers, and from the Kimberley District.

Triassic Crinoids.—

The Kaihiku Series of Nelson, New Zealand, has yielded some crinoid stems, but the genus has not yet been determined.

Cretaceous Crinoids.—

In the Lower Cretaceous Limestone of Queensland, at Mitchell Downs and Wollumbilla, a typical Crinoid, closely allied to the living Pentacrinus is found, namely, Isocrinus australis (Fig. 76 F).

The Upper Cretaceous opal deposits of White Cliffs in Wilcannia, New South Wales, contain many opalised fossil remains, amongst them being Isocrinus australis, already noticed as occurring in the Lower Cretaceous of Queensland.

Cainozoic Crinoids.—

Pentacrinus stellatus is a species founded on some deeply indented pentagonal stem-joints found in the Oamaru Series (Miocene) at Curiosity Shop, South Canterbury, New Zealand, and also occurring in the Chatham Islands. This species has been identified in the Aire Coastal beds in Victoria, of the same age. Another generic type, Antedon, the beautiful “Feather Star,” is frequently met with in Janjukian strata in Victoria and South Australia, as at Batesford and Mount Gambier, represented by the denuded crown and the ossicles of the arms of a comparatively large species; whilst another and smaller form has been described from beds of the same age from borings in the Victorian Mallee, under the name of A. protomacronema.

BLASTOIDEA—Bud-shaped Echinoderms.

Distribution and Characters of Blastoidea.—

This forms a small class which has a few representatives in the rocks of Australia. Elsewhere they are chiefly of Devonian and Carboniferous ages. In Australia they are confined, so far as known, to sediments of the Carboniferous System. The animal was rooted to the sea-floor and a jointed stem was usually present. The cup or theca, as before noted, is bud-shaped, and consists of basal, radial and deltoid plates, the edges of which are folded inwards into the thecal cavity, and thus the internal organs came into contact with the incurrent water. The cup bears five food grooves, bordered by numerous arms or brachioles, which directed the incurrent particles into the thecal cavity.

Carbopermian Blastoids.—

Three genera of blastoids have been recorded from the Gympie Beds, or Carbopermian, of the Rockhampton District of Queensland. They are, Mesoblastus, Granatocrinus and Tricoelocrinus. A similar fossil in beds of like age, and provisionally referred to the genus Metablastus, has been lately recorded from Glenwilliam, Clarence Town, New South Wales.

ASTEROIDEA, or Starfishes.

Characters of True Starfishes.—

These free-moving echinoderms are usually five-sided, though sometimes star-shaped, with numerous arms surrounding a central disc. The mouth is central on the under side of the disc, and the anus above and near the centre (excentric), the latter being covered by a porous plate called the madreporite. The hydraulic system of starfishes consists of tubes extending along the grooved arms and giving off side branches which end in processes called podia and terminating in suckers. The podia pass through pores in the floor plates of the grooves, and communicate within the body with distensions called ampulla. By this means the podia serve as feet, and can be withdrawn by the expulsion of the water in them into the ampulla. The stout flexible covering of the starfish is strengthened by calcareous plates and bars, owing to the presence of which they are often preserved as fossils.

Silurian Starfishes.—

The oldest Australian fossil Starfishes are found in the Silurian. In Victoria they occur in some abundance in the lower, Melbournian, series, but appear to be absent or at all events very scarce in the upper, or Yeringian series. The commonest genus is Palaeaster, of which there are two species, P. smythi (Fig. 77 A) and P. meridionalis, found alike in the sandy and argillaceous strata near Melbourne. Urasterella is another genus found in the Silurian rocks near Melbourne, in which the marginal series of plates seen in Palaeaster are wanting, giving to the starfish a slender, long-armed aspect (Fig. 77 B).

Carbopermian Starfishes.—

In the Lower Marine Series of the Carbopermian of New South Wales a very large species of Palaeaster occurs (P. giganteus), measuring 7 inches from point to point across the disc (Fig. 77 C). Two other species of the same genus occur in this series (P. stutchburii and P. clarkei) the latter also ranging into the Upper Marine Series.

Cainozoic Starfishes.—

No remains of true Starfishes have been recorded from Australia between the Carbopermian and the Tertiary systems. In the Janjukian Series of Victoria the marginal plates of a species of Pentagonaster are typical fossils. They have been recorded from Waurn Ponds, Spring Creek near Torquay, and Batesford (Fig. 77 D). In the Mallee Bores, both marginal and abactinal plates of this genus are found in polyzoal limestone (Miocene). Pentagonaster also occurs in the Lower Muddy Creek beds (Oligocene), and the Upper beds of the same locality (Lower Pliocene). A species of Astropecten has been described from the Waikari River, New Zealand (Oamaru Series).

OPHIUROIDEA, or Brittle-stars.

Characters of Brittle-Stars.—

The Brittle-stars are frequently found at the present day cast up on the fine sandy beaches of the coast. They are easily distinguished from true starfishes by having a definite central disc, to which the arms are attached. The arms are used for locomotion and prehension, and have their grooves covered over with plates. The ossicles of the arms are moveable and controlled by muscles which enable them to be used as feet. The lower surface of the disc has a central arrangement of five rhomboidal sets of jaws, formed of modified ossicles, called the mouth frame, whilst the upper surface bears, between one set of arms, the madreporite or covering plate to the water vascular system, as in starfishes.

Silurian Brittle-Stars.—

The Brittle-stars in Australia first appear in the Silurian, but in England and Bohemia date back to the Ordovician. Protaster is the commonest genus, and is represented by P. brisingoides of the Melbournian stage of Silurian strata at Flemington (Fig. 78). It also occurs rarely in the Yeringian beds at Yering, both Victorian localities. A very ornamental form, Gregoriura spryi, occurs in the same division of the Silurian at South Yarra. In this fossil the delicate spines attached to the adambulacral ossicles are well preserved and form a marginal fringe to the arm (Fig. 79). Sturtzura is another Silurian genus, found in the Wenlock of England and in the Melbournian of Flemington, Victoria.

Cainozoic Brittle-Stars.—

From the Victorian Cainozoic beds, in the Lower Pliocene of Grange Burn, Hamilton, a vertebral ossicle of an ophiurian has been obtained, which has been provisionally referred to the genus Sigsbeia.

ECHINOIDEA, or Sea-urchins.

This group is an important one amongst Australian fossils, especially those of Cainozoic age.

Characters of Sea-urchins.—

Echinoids are animals enclosed in a spheroidal box or test composed of numerous calcareous plates, disposed geometrically as in the Starfishes, along five principal lines. The test in the living condition is more or less densely covered with spines. The mouth is on the under surface. The anus is either on the top of the test (dorso-central), or somewhere in the median line between the two lower ambulacra. The ambulacra (“a garden path”) are the rows of perforated plates on the upper (abactinal) surface sometimes extending to the lower surface, through which protrude the podia, which in Starfishes are situated in grooves on the lower surface.

Silurian Palaeechinoids.—

The Palaeechinoids are represented in the Silurian of Australia by occasional plates, as at Bowning, New South Wales, and near Kilmore, Victoria, whilst spines are not uncommon in certain Silurian limestones at Tyer’s River, Gippsland.

Carbopermian Palaeechinoids.—

In the Carbopermian of New South Wales, tests of Archaeocidaris have been recorded, and also a plate of the same genus in the Gympie Beds of Rockhampton, Queensland.

Regular Echinoids.—

The regular Echinoids date from Permian times. They have two vertical rows of plates for each ambulacrum and inter-ambulacrum. The mouth is on the underside, and the anus abactinal (on the upper side) and near the centre.

Cainozoic Regular Echinoids.—

In Australasia they make their first appearance in strata of Tertiary age, and some species, as Paradoxechinus novus, range through Balcombian strata to Kalimnan in Victoria, or Oligocene to Lower Pliocene, but are more typically Janjukian. Echinus (Psammechinus) woodsi (Fig. 80 B) is common in Janjukian strata in Victoria and South Australia and occurs sparingly in the Kalimnan. Another common form of the regular Echinoids in Southern Australia is Cidaris australiae (Fig. 80 A), ranging from Janjukian to Kalimnan, occurring more frequently in the older series. In New Zealand a species of Cidaris (C. striata), is known from the Oamaru Series at Brighton. An Echinus occurs in the Oamaru Series of Broken River, and two species of that genus in the Wanganui formation of Shakespeare Cliff. Temnechinus macleayana has been recorded from the Cainozoic (Miocene or Pliocene) of Yule Island, Papua.

Irregular Echinoids.—

The irregular Echinoids are not known before the Upper Cretaceous in Australia, and are very common in the Tertiaries. They are distinguished by the anus (periproct) passing backward from the apex, as compared with the regular forms, and by the elongation of the test and the loss of the strong solid spines, which are replaced by thin, slender hair-like spines. The animal is thus better fitted to burrow through the ooze on which it feeds.

Cretaceous Irregular Echinoids.—

An interesting form, Micraster sweeti, is found in the Upper Cretaceous or Desert Sandstone of Maryborough in Queensland, which reminds one of typical European species of this genus.

Cainozoic Irregular Echinoids.—

Amongst the Australian Cainozoic Echinoids of the irregular type the following may be mentioned. The little subglobular test of Fibularia gregata, and Echinocyamus (Scutellina) patella (Fig. 80 C, D) are Janjukian in age. The large Clypeaster, C. gippslandicus (Fig. 80 E), ranges from the Oligocene to Lower Pliocene in Victoria (Balcombian to Kalimnan), and vies in size, especially in the Janjukian, with some large species like those from Malta and Egypt. This genus includes some of the largest known sea-urchins. The biscuit urchin, Arachnoides (Monostychia) australis, is commonest in the Janjukian, but ranges from Balcombian to Kalimnan. A common urchin from the polyzoal rock of Mt. Gambier is Echinolampas gambierensis, which is also found in the Lower beds of Muddy Creek. A typical Janjukian fossil is Duncaniaster australiae, formerly thought to belong to the Cretaceous genus Holaster. Although found living, the genus Linthia attained its maximum development both in size and abundance, in Janjukian or Miocene times, as seen in L. gigas (having a length of 7¹/₂ inches) and L. mooraboolensis. Echinoneus dennanti is restricted to the Janjukian. Several species of Eupatagus occur in the Cainozoic or Tertiary beds of South Australia, Victoria and New Zealand; Lovenia forbesi (Fig. 81 C) is common in the Janjukian to Kalimnan, both in Victoria and South Australia. In the latter State also occur the following genera:—Studeria, Cassidulus, Echinolampas, Plesiolampas, Linthia, Schizaster and Brissopsis. In New Zealand the following Cainozoic genera, amongst others of the irregular sea-urchins, may be cited:—Hemipatagus, Brissopsis, Hemiaster, and Schizaster (Fig. 81).

A clypeastroid, Peronella decagonalis has been described from the (?) Lower Pliocene of Papua.

Cainozoic Holothuroidea.—

The HOLOTHUROIDEA (Sea-Cucumbers) are represented in Australian deposits by a unique example of a dermal spicule of wheel-like form, referred to Chiridota, obtained from the Cainozoic (Janjukian) beds of Torquay. This genus is also known from the “calcaire grossier” or Middle Eocene of the Paris Basin, and is found living in all parts of the world.

COMMON OR CHARACTERISTIC FOSSILS OF THE FOREGOING CHAPTER.

CRINOIDS.

(?) Pisocrinus yassensis, Eth. fil. Silurian: New South Wales.

Helicocrinus plumosus, Chapman. Silurian: Victoria.

Botryocrinus longibrachiatus, Chapm. Silurian: Victoria.

Hapalocrinus victoriae, Bather. Silurian: Victoria.

Actinocrinus sp. Carboniferous: Queensland.

Cyathocrinus sp. Carboniferous: New Zealand.

Phialocrinus konincki, Clarke sp. Carbopermian: New South Wales.

Phialocrinus princeps, Eth. fil. Carbopermian: New South Wales.

Tribrachiocrinus clarkei, McCoy. Carbopermian: New South Wales.

(?) Platycrinus sp. Carbopermian: Queensland.

Platycrinus sp. Carbopermian: W. Australia.

Isocrinus australis, Moore sp. Cretaceous: Queensland.

Pentacrinus stellatus, Hutton. Miocene: New Zealand, Chatham Ids. and Victoria.

Antedon protomacronema, Chapman. Miocene: Victoria (deep borings).

BLASTOIDS.

(?) Mesoblastus australis, Eth. fil. Carbopermian: Queensland.

STARFISHES.

Palaeaster smythi, McCoy. Silurian: Victoria.

Palaeaster meridionalis, Eth. fil. Silurian: Victoria.

Urasterella selwyni, McCoy. Silurian: Victoria.

Palaeaster giganteus, Eth. fil. Carbopermian (L. Mar. Ser.): New South Wales.

Palaeaster clarkei, de Koninck. Carbopermian (L. and Up. Mar. Ser.): New South Wales.

Pentagonaster sp. Miocene: Victoria.

Astropecten sp. Miocene: New Zealand.

BRITTLE-STARS.

Protaster brisingoides, Gregory. Silurian: Victoria.

Gregoriura spryi, Chapman. Silurian: Victoria.

Sturtzura leptosomoides, Chapman. Silurian: Victoria.

(?) Sigsbeia sp. Lower Pliocene: Victoria.

ECHINOIDS.

Palaeechinus sp. Silurian: Victoria.

(?) Archaeocidaris selwyni, Eth. fil. Carbopermian: New South Wales.

Micraster sweeti, Eth. fil. Cretaceous: Queensland.

Cidaris (Leiocidaris) australiae, Duncan. Miocene and Lower Pliocene: Victoria and S. Australia.

Cidaris striata, Hutton. Miocene: New Zealand.

Echinus (Psammechinus) woodsi, Laube sp. Miocene and L. Pliocene: Victoria and S. Australia.

Temnechinus macleayana, T. Woods. Cainozoic (? Lower Pliocene): Papua.

Fibularia gregata, Tate. Miocene: Victoria and S. Australia.

Echinocyamus (Scutellina) patella, Tate sp. Oligocene to Miocene: Victoria and S. Australia.

Clypeaster gippslandicus, McCoy. Oligocene to L. Pliocene: Victoria.

Arachnoides (Monostychia) australis, Laube sp. Oligocene to L. Pliocene: Victoria and S. Australia.

Echinoneus dennanti, Hall. Miocene: Victoria.

Duncaniaster australiae, Duncan sp. Miocene: Victoria.

Lovenia forbesi, T. Woods sp. Miocene and L. Pliocene: Victoria and S. Australia.

Hemiaster planedeclivis, Gregory. Miocene: Victoria.

HOLOTHURIAN.

Chiridota sp. Miocene: Victoria.

LITERATURE.

CRINOIDS.

Silurian.—Etheridge, R. jnr. Rec. Austr. Mus., vol. V. No. 5, 1904, pp. 287-292 (Pisocrinus). Bather, F. A. Geol. Mag., Dec. XV. vol. IV. 1897, pp. 337-345 (Hapalocrinus). Chapman, F. Proc. R. Soc. Vict., vol. XV. (N.S.), pt. II. 1903, pp. 107-109 (Helicocrinus and Botryocrinus). Bather, F. A. Ottawa Nat., vol. XX. No. 5, 1906, pp. 97, 98.

Carboniferous and Carbopermian.—De Koninck, L. G. Mem. Geol. Surv. New South Wales, Pal. No. 6, 1898, pp. 121-126. Etheridge, R. jnr., in Geol. and Pal. Queensland, 1892, pp. 207-219. Idem, Mem. Geol. Surv. New South Wales, Pal. No. 5, 1892, pp. 75-119.

Cretaceous.—Moore, C. Quart. Journ. Geol. Soc., vol. XXVI. 1870, p. 243. Etheridge, R. jnr., in Geol. and Pal. Queensland, 1892, p. 439 (Isocrinus).

Cainozoic.—Hutton, F. W. Cat. Tert. Moll. and Ech. of New Zealand, 1873, p. 38.

BLASTOIDS.

Carbopermian.—Etheridge, R. jnr., in Geol. and Pal. Queensland, 1892, pp. 210-213. Taylor, T. G. Proc. Linn. Soc. New South Wales, 1908, pp. 54-59 (? Metablastus).

STARFISHES.

Silurian.—McCoy, F. Prod. Pal. Vict., Dec. I., 1874, pp. 41-43. Etheridge, R. jnr. Rec. Austr. Mus., vol. I., No. 10, 1891, pp. 199, 200.

Carboniferous and Carbopermian.—Etheridge, R. jnr. Mem. Geol. Surv. New South Wales, Pal. No. 5, pt. 2, 1892, pp. 70-75. De Koninck, L. G. Ibid., Pal. No. 6, 1898, p. 127.

Cainozoic.—Hall, T. S. Proc. R. Soc., Vict., vol. XV. (N.S.), pt. I. 1902, pp. 81, 82 (Pentagonaster). Hutton, F. W. Cat. Tert. Moll, and Ech. New Zealand, 1873, p. 38.

BRITTLE-STARS.

Silurian.—Gregory, J. W. Geol. Mag., Dec. III. vol. VI. 1889, pp. 24-27. Chapman, F. Proc. R. Soc. Vict., vol. XIX. (N.S.), pt. II. 1907, pp. 21-27.

Cainozoic.—Hall, T. S. Proc. R. Soc. Vict., vol. XV. (N.S.), pt. I. 1902, p. 82 (cf. Sigsbeia).

ECHINOIDS.

Silurian.—Chapman, F. Rec. Geol. Surv. Vict., vol. II. pt. 1, 1907, pp. 77, 78.

Carbopermian.—Etheridge, R. jnr. Mem. Geol. Surv. New South Wales, Pal. No. 5, pt. 2, 1892, pp. 67-69.

Cretaceous.—Etheridge, R. jnr., in Geol. and Pal. Queensland, 1892, pp. 559, 560.

Cainozoic.—T. Woods. Trans. Adelaide Phil. Soc., 1867. Laube, G. C. Sitz, k. k. Ak. Wiss. Wien, vol. LIX. 1869, pp. 183-198. Hutton, F. W. Cat. Tert. Moll, and Ech. New Zealand, 1873, pp. 38-43. Duncan, P. M. Quart. Journ. Geol. Soc., vol. XXXIII. 1877, pp. 42-73. Tate, R. Quart. Journ. Geol. Soc., vol. XXXIII. 1877, pp. 256-258. Idem, Southern Science Record, 1885, p. 4. Idem, Trans. R. Soc. S. Austr., vol. XIV. pt. 2, 1891, pp. 270-282. McCoy, F. Prod. Pal. Vict., Dec. VI. VII. 1879, 1883. Gregory, J. W. Geol. Mag., Dec. III. vol. VII. 1890, pp. 481-492. Ibid., Dec. III. vol. IX. 1892, pp. 433-437. Cotteau, G. H. Mem. Zool. France, vol. II. No. 4, 1889, p. 228; vol. III. No. 5, 1890, pp. 537-550; vol. IV. No. 5, 1891, pp. 620-633. Bittner, A. Sitz. k.k. Ak. Wiss. Wien, 1892, vol. 101, pp. 331-371. Hall, T. S. Proc. Roy. Soc. Vic., vol. XIX. (N.S.), pt. II. 1906, pp. 48, 53. Chapman, F. Proc. Roy. Soc. Vict., vol. XX. (N.S.), pt. II. 1908, pp. 214-218. Pritchard, G. B. ibid., vol. XXI. (N.S.), pt. I. 1908, pp. 392-400.

HOLOTHURIAN.

Cainozoic.—Hall, T. S. Proc, R. Soc. Vict., vol. X. (N.S.), pt. I. 1902, pp. 82, 83.