GE OL O GICAL DIS TRIE UTION 



TABLE II 



THE DISTRIBUTION OF FISHES IN GEOLOGICAL TIME 



The geological distribution of the prominent groups of fishes as here shown is in the main 

 as given by Zittel (Palseontologie: Fische). The varying thickness of the lines denotes ap- 

 proximately increase or diminution in the number of existing genera. 





m 



a 

 o 



> 



Q 



c 2 



a 





t/i 



O 



0) 



c 



4) 

 (J 



o 



a 



o 



o 



c 



O 



o 



U 



MarsipobrancMi . 



Cyclostomes . 

 ?Pteraspids . . 

 PCephalaspids . 



Palaeospondylus 



PPterichthids . 



ElasmobrancMl. 



Cladoselache . . 

 Acanthodians . 

 Pleuracanthids 

 Cestracionts . . 

 Recent sharks (in 

 eluding Notidanids) 



Rhinobatus . . . 



Pristis 



Pristiophorus . . . 

 Rays 



Chimaeroids . . . . 



Dipnoans. 



Dipterus , . . . 



Ceratodus . . . . 



?Arthrodira .... 



Teleos tomes. 



Crossopterygians , 

 Acipenseroids . . 

 Lepidosteoids . . 

 Amioids .... 

 Clupeoids . . . 

 Salmonids . . , 

 Perches and Bery 



cids 



Siluroids . . . 



Gadoids and other 



Teleosts . . . . 



