68 







THE CHRONOLOGICAL DISTRIBUTION 









Devonian. 



Subcarbon. 



Coal-meas. 



Permian. 



Trias sic. 



Jurassic. 



Cretaceous. 



liocenc. 



Miocene. 



Pliocene. 















Rnjidtz 



Raja 

 Cyclobatis 



Raja 



riatyrhina 

 Narcobatidcs 



Raja 

 Acanthobatis 



Raja 

 Oncobatis 

































Pristidce 



Narcobatus^ 

 Narcine 































Sclerorhyn- 



[chus 



Pristis 



Amblypristis 



Propristia 



Pristis 

















Dasyalida 





















Dasyatis" ? 



Dasyatis 

 Urol oph us 

 Xyphotrygon 



Dasyatis 



Dasyatis 



















Myliobatidai 





















Myliobatis? 



Myliobatis? 

 Rliinoptera? 

 AiUobatis? 

 Rhombodus 



Ptyckodon- 



\Jid<E 



Myliobatis 

 Rliinoptera 

 Aetobatis 

 Promyliobatis 



Myliobatis 

 Rliinoptera 

 Aiitobatis 



Myliobatis; 

 Rhinoptera 



Aolobatis 



Ptyctodontida 







Omlcodus? 



- 





Ptychodus 



i Irmiplycho- 



[dus 









Ptyctodus 



Rhynchodus 



Palneomylus 











Squalornjida 

 Squaloraja 



Myriacan- 



[/ 'hides 



Myriacanthus 

 ( 'himasrops 



Chimesrida 









• 













Ganodus 



Ischyoilns 



Edaphodon 

 Ischyodus 

 Elasmodus 

 1 .eptomylus 



Elasmodectes 

 Bryactinus 



Spliagepu'a 



[sotsenia 



Edaphodon 



Mylognathus 

 Elasmodus 



Edaphodon? 



Chimiura? 



Chimsera 



1 Diplodus . 



to be i 

 tins gili 



2 Dicrenodu 



1 Ac.-uithodi 

 * Xystrodiis 

 6 Goniodus '. 

 6 Tomodus 1 



Lg.'; type of 

 9. diverge/is < 



bosun Ag. 



S Rom. 



s. 



Ag. 



^ewb. 



)avis. 



[>i1 l.odus Owe 

 )wen — Dip! 



:n ' Stem 

 o- 8 Cest 

 » Noti 

 '" Orth 

 " Odd 

 12 Oxyt 

 1:1 Soy] 

 14 Care 



malodus St. • 

 acion ( 'in . 

 lanua Cuv. 

 icodus A. S. 

 tagpie Ag. 

 hina Ag. 



iuiu Cuv. 

 larias Raf. 



r. & w. 

 w. 



15 



to 



17 

 18 

 19 



ft 



Galeus Cuv. 

 Scymnus Cu 

 Spinas < !uv. 

 Torpedo Dui 



Trygon Cuv 

 On the aiillii 



V. 

 u. 

 rity of Dr. C. 



R. Eastman. 



