Stewart.] Cretaceous Fishes. ;$03 



dyle of the maxilla is slightly concave and much broader than 

 the condyle articulating with it, thus forming a rather loose 

 union. 



There are numerous vertebra* present which show them to 

 be two-grooved, and, with the exception of the difference in 

 size, very similar to those of I. anaides. The pectoral fin is 

 represented in a somewhat fragmentary condition, but enough 

 of the rays are present to show that the upper ones are sword- 

 like and but slightly less curved than in Xiphactinus, The 

 pelvic actinosts are very similar in many respects to those of 

 the genus just mentioned. The two halves are strongly sutured 

 together in the median line, where the bones are massive for 

 the support of the pelvic fin. The facets are obliquely set and 

 are four in number on each side. The upper and lower of these 

 are large and flat, while the two median ones are round and 

 somewhat tubercular. Extending forward, both above and be- 

 low, there are ridges of bone wmich are not so prominent as in 

 Xiphactinus, which may have formed bars of bone on each side. 

 External to these there are wing-like processes. 



Ichthyodectes ctenodon. Plate XLIX, figs. 5-7; plate LI, figs. 12, 13. 

 Tchthyodectes ctenodon Cope, Proc. Am. Phil. Soc. 1870, p. 536. 



There is one specimen, consisting of the mandibles, a portion 

 of a maxilla, and other bones, which do not seem to differ ma- 

 terially from those of the specimen described and figured by 

 Professor Cope. It evidently does not belong to any of the other 

 American species, and for the present at least I will leave it here. 



The dentary is about the same size as that of /. anaides, de- 

 scribed above, but differs from this in the absence of the pos- 

 terior convexity of the alveolar border. This border unites 

 with the symphysis at an angle of about 75 deg., which is 10 

 deg. more than Cope describes of his specimen. There seems 

 to be some discrepancy between Cope's description and figure, 

 for in the latter the angle seems to be about the same as in our 

 specimen, which evidently shows that Cope was wrong in one of 

 the two. The teeth are large anteriorly but somewhat smaller 

 posteriorly, round in section, non-striate, and directed inward. 



