Stewart.] Cretaceous Fishes. 349 



SALMONID^E. 

 Pachy rhizodontidce Cope, Proc. Am. Phil. Soc, vol. xn, p. 343. 



Iii the year 1873 Professor Cope described his family Pachy- 

 rhizodontidx, to include the genus Pachy rhizodus } and which he 

 characterized as follows : 106 " This family of physostomous fishes 

 differs from the last, Saurodontidse and Ichthyodectidss, in the na- 

 ture of its dentition. Instead of elongated conic fangs sunk in 

 deep alveoli, it has shorter and stouter fangs occupying alveoli, 

 of which the inner side and part of the antero-posterior walls 

 are incomplete. The teeth are, in fact, more or less pleurodont, 

 but the extremity of the root is received into the conic fundus 

 of the alveolus. 



11 The premaxillary bones are well developed, but the maxilla- 

 ries are more so, and enter largely into the composition of the 

 border of the mouth. There is a well-developed angle of the 

 mandible, but no coronoid bone is preserved in the specimens. 

 The coronoid region is, however, broken in all of our specimens. 

 The other characters of the family are not determinable from 

 our imperfect material." 



In the " Cretaceous Yertebrata," published in 1875, Professor 

 Cope abandons the name Pachyrhizodontidse and includes Pachy- 

 rhizodus in his family Stratodontidtr , to which it evidently does 

 not belong. It seems to show some relation to the Salmonidse, 

 in which family it should probably be included, along with Ori- 



cardinus. 



PACHYRHIZODUS. 



Dixon, Geol. of Sussex, p. 374, 1850. 



The muzzle of this genus is flat and the bones of the skull 

 more fragile than in members of the Tchthyodectida and Sauro- 

 dontida , consequently indicating a less powerful and rapacious 

 fish than those belonging to these families. The mandibles are 

 loosely united at the symphysis and bear a single row of teeth 

 which are somewhat pleurodont, sharply pointed, and bear a 

 superficial resemblance to some of the Mosasaurs. Their mode 



106. i. c, p. Ma 



