genera which entered Australasia during the early and mid-Oligocene, Phyllacanthus and Cyclaster had already become established in northern India in the Eocene. Fibularia, Studeria, Pericosmus and Lovenia likewise occur in the Eocene of Egypt, though they do not occur in Australasia till the Oligocene. Echinolampas, another Oligocene immigrant to Australasia, had had a wide northern distribution in the Eocene, in India, Borneo, North Africa, and Europe. Pericosmus had also occurred in the Eocene of Persia, and reached India by the Oligocene at least, probably earlier. Linthia, Schizaster and Brissopsis had all had a widespread northern distribution during Cretaceous and Eocene times. The remaining Oligocene genera, Duncaniaster, Goniocidaris and Brochopleurus are not known earlier in the geological record; they probably originated within the Australasian region, and will be further considered below. Of late Tertiary and Recent immigrants to Australasia, Centrostephanus and Echinocardium had already appeared in Europe in the Miocene,Brissus in the Miocene of Java, Laganum in the Eocene of the Mediterranean. Holopneustes and Pseudechinus are perhaps Australasian derivatives of the Temnopleurid stock previously present in the Miocene. Clypeaster is probably an immigrant from the north-west Pacific, from an original Pliocene Californian stock. Arachnoides and Monostichia are Australasian.

(b) Tertiary Genera of New Zealand, Not Yet Known From Australia.

Galeraster and Echinocorys, in the New Zealand Eocene and Oligocene, are the last remnants of ancient northern stock. Grammechinus, in the lower Oligocene, seems to have been the first of its type-it reappears in the Miocene of India, and is known only from these two records. The genera Evechinus and Ogmocidaris are both restricted to the New Zealand submarine plateau, the former first appearing in the mid-Pliocene.

(c) Tertiary Genera of Australia, Not Yet Known from New Zealand.

Echinoneus, Sismondia, Conoclypus, Cassidulus, Prenaster and Plesiolampas all had Eocene representatives in India or Europe; they are not known from Australia earlier than the Janjukian, save for Prenaster, which occurs in an Aldingan (lower) sediment, attributed to the late Eocene. Coelopleurus occurred throughout the Oligocene in India; it is present in the Australian Janjukian.

Indo-Pacific Origin.

From the foregoing we may conclude that the main source of the Australasian Tertiary echinoderm faunas has been the old world, and more particularly, the northern Indo-Pacific region. Genera which occur in India in the Cretaceous reached Australasia in the Eocene. Genera which occur in the Indian Eocene reached New Zealand by the early or mid-Oligocene; they may well have reached Australia at the same time, but the absence of earlier Oligocene beds from Australia precludes our recognizing these forms earlier than the Janjukian. This Old Indo-Pacific stock, as it might be termed, seems to have remained with but little change until the close of the Miocene. Then, with extinction of the old fauna, came a New Indo-Pacific stock, which, together with stock of Australasian origin, brought into being the late Tertiary and Recent faunas. We find the earliest members of this new stock in the Waitotaran and Nukumaruan stages of the New Zealand early and mid-Pliocene and in the Kalimnan (early Pliocene) of Australia.