The Chondrostei and Holostei 339 



species from the same strata, but also by two species from 

 like beds of Ain in France, and still others from the more 

 recent Purbeck beds of Dorset, England; Pappichthys with 

 related types Protamia and Amiopsis from the lower fresh- 

 water Eocene of W. America and of France; and Amia 

 that probably evolved first in central N. America during 

 early Eocene times, reached western Europe in late Eocene 

 times to die out there by close of the Miocene period, but 

 which still persists as Amia calva — the bow-fin — over a 

 large area of the lake and river regions of N. America. 



iVll of them evolved in, and remained in, freshwater 

 regions, as is shown by the rocks in which they occur; the 

 immediately associated fossils; the continued persistence of 

 the three last-named genera amongst the ramified Eocene- 

 Miocene lake-system of Western America, as outlined by 

 Cope and others; also by the survival of Amia over an even 

 more expanded territory probably at the present day. 



The last of the protospondylean groups is the Aspido- 

 rhynchidae that includes Aspidorhynchus and Belonostomus. 

 These with the still-surviving Lepidosteus of the family 

 Lepidosteidae, make up a morphologically transition as- 

 semblage between the protospondylean and teleostean divi- 

 sions that has been named the Aetheospondyli, on account 

 of the progressively advancing evolution of the vertebral 

 column. 



The above two genera both appear first in the litho- 

 graphic stone of Bavaria and France, and from the mixed- 

 up nature of the organic contents in the former it would 

 be hazardous to suggest the natural environal habitat. But 

 the list of fishes and other organisms, given by Thiolliere 

 and subsequent collaborators, from Bugey {242) helps 

 more perfectly when one compares this with the exact 

 stratigraphic descriptions given jointly by M. M. Falsan 

 and Dumortier. Then one learns that from the "Bajocien" 

 and Bathonian upward to the Corallian the beds and their 

 included fossils are marine. No fish remains occur amongst 

 these. But at the top of the Corallian or base of the 

 Kimmeridgean occurs a bed with Ostrea virgula, and just 

 above this the fauna changes, the palaeontological facies 

 is modified, and there is ushered in the richly bituminous 



