GEOLOGICAL DISTRIBUTION 



9 



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 (Palaeontologie: Fische). The varying thickness of the lines denotes ap- 

 proximately increase or diminution in the number of existing genera. 



3 



Q 





MarsipobrancMi. 



Cyclostomes . 

 ?Pteraspids . . 



PCephalaspids . 

 Palaeospondylus 

 ?Pterichthids . 



Elasmobranchii. 



Cladoselache . . 



Acanthodians . . 

 Pleuracanthids 



Cestracionts . . 



Recent sharks (in 

 eluding Notidanids) 



Rhinobatus . . . 



Pristis 



Pristiophorus . . . 

 Rays 



Chimaeroids . . . . 



Dipnoans. 



Dipterus . . . 



Ceratodus . . . 



?Arthrodira . . . 



Teleostomes. 



Crossopterj'gians . 

 Acipensernids . 

 Lepidosteoids . . 

 Amioids .... 

 CUipeoids . . 



Salmonids ... 

 Perches and Bery 



cids 



Siluroids ... 

 Gadoids and other 

 Teleosts . . . . 



