Phyllocarids of the Lower Ordovician slates are referred to the genera Rhinopterocaris, Caryocaris, Saccocaris and Hymenocaris. The first-named is the commonest type; and is found in slates of the Lancefield, Bendigo and Castlemaine Series at the localities named, as well as at Dromana. Rhinopterocaris ([Fig. 118 A]) is readily distinguished by its long—ovate outline, and this, together with its wrinkled chitinous appearance makes it resemble the wing of a dipterous insect. Caryocaris ([Fig. 118 B]) is a smaller and narrower form which occurs in the Victorian Lower Ordovician slates, as well as in ice-borne blocks derived from the Ordovician, at Wynyard, in N.W. Tasmania.
Silurian Phyllocarids.—
The chief type of Phyllocarid in the Silurian is Ceratiocaris ([Fig. 119]). The carapace is typically ovate, straight on one edge, the dorsal, and convexly curved on the other, the ventral. They resemble bean-pods in outline, hence the name “pod-shrimps.” Several species are known from the Victorian shales, mudstones, and sandstones; the forms found in Australia if complete would seldom attain five inches in length, whilst some British species are known to reach the exceptional length of two feet. The long, grooved and jointed telson is not uncommon in the sandstones of Melbourne and Kilmore. Other genera described from Victoria are Aptychopsis and Dithyrocaris.
Lower Cretaceous Crab.—
The earliest example of the DECAPODA in the Australian rocks, so far recorded, is the Lower Cretaceous Prosopon etheridgei ([Fig. 120 A]) from Queensland, which has affinities with some Jurassic and Neocomian crabs found in Europe. Other crustacean remains of less decipherable nature occur in this same deposit.
Fig. 120—FOSSIL CRABS and INSECTS.
A—Prosopon etheridgei, H. Woodw. L. Cretaceous. Queensland
B—Ommatocarcinus corioensis, Cressw. sp. Cainozoic (Jan.) Vic.
C—Harpactocarcinus tumidus, H. Woodw. Cainozoic (Oamaru). New Zealand
D—Aeschna flindersensis, H. Woodw. L. Cretaceous. Queensland
E—Ephemera culleni, Eth. fil. and Olliff. Cainozoic (Deep Leads). New South Wales
Cainozoic Crabs.—
Of the Cainozoic decapod Crustacea there is a Victorian species of a stalk-eyed crab, Ommatocarcinus corioensis ([Fig. 120 B]), found in the marls of Curlewis and Port Campbell, and probably of Janjukian age. Various portions of similar Crustacea, consisting of claws and fragmentary carapaces, are found from time to time in the Victorian clays and limestones of Balcombian and Janjukian ages, but they are insufficient for identification. A carapace of one of the Oxystomata (with rounded cephalo-thorax and non-salient frontal region) has occurred in the Kalimnan marl of the Beaumaris Cliffs, Port Phillip. It is closely allied to a crab now found in Hobson’s Bay and generally along the Victorian coast.