244 CENSUS OF THE OLDER TERTIARY FAUNA OF AUSTRALIA. 



The percentage numbers of the two largest classes, Gastropoda 

 and Lamellibranchiata are as follows : — 





Gastropoda. 



Lamellibranchiata. 



New South Wales ... 



68-64 . 



31-36 



Tasmania 



732 



26-8 



South Australia 



68-1 



31-9 



Mean 69*3 ... 317 



Older Tertiary of Australia 74'8 ... 25'2 



The high ratio of the Gastropods to the Lamellibranchs in the 

 Old Tertiary Fauna is not unexpected, and when the Gastropods 

 shall have been more fully elaborated the differences will be 

 intensified. 



It would have been desirable in our comparison of the living 

 and fossil faunas, that the recent species of our provincial lists 

 had been concreted ; but this is not possible until the claims 

 of a very large number of Tasmanian species to rank as peculiar 

 have been firmly established. 



The comparative richness in species of Palliobranchs, corals and 

 echinoids and in a less degree of polyzoa, is a distinguishing 

 feature between the Recent and Old Tertiary faunas of Australia. 

 The numerical strength of the Palliobranchiata is paralleled in 

 the Italian Eocene, and the generic variety in the Echinodermata 

 by the Maltese Miocene and the Scindian Nummulitic. 



The specific relations are few, except among the polyzoa, 

 entomostracans and foraminifera, so far as the determinations 

 have been made. In Vertebral a and Cephalopoda there are 

 none; less than a dozen of Gastropoda, and not many more of 

 Lamellibranchiata, in both classes the specific identities are more 

 or less protean species. There is at least one living species of 

 Palliobranchiata, and nearly one-half of the Polyzoa survive to 

 the present day, though of the Cyclostomatous order there are only 

 three species in recent creation out of a total of 22, whilst a few 

 antedate to Cretaceous. The echinoderms are all extinct, though 

 Schizaster ventricosus and Echinanthus testudinarius have 

 erroneously been quoted. Corals have three or four identities, 

 one only Australian ; and all, or nearly all, the foraminifers as 

 might be expected are living, the Eocene Nummulites being the 

 most marked exception. 



The total living species in the classes indicated in the 

 accompanying list is 31, which out of a total of 1046, represents 

 only 3 per cent. Of the 31, 14 are found in the Lower Series or 

 Eocene, whilst 21 are actually known in the Upper Series or 

 Miocene and by inference the additional 10 which pass up from 

 the Eocene though yet undiscovered in the Miocene. Complete 

 lists of the fauna of each subdivision of the Older Tertiary have 



