Stewart. I Cretaceous Fishes. 353 



In addition to the above there is a tooth-bearing element that 

 may be a portion of the maxilla, but I think the teeth are too 

 small to be a part of this bone. The teeth are closely set upon 

 small, bony rostrums similar to those of the lower jaw. The 

 external surface is nearly smooth. 



Mandible: Length of alveolar border 110.5 mm. 



Length from cotyloid cavity 123.0 " 



Depth at coronoid angle (estimated) 20.0 " 



Number of teeth in one inch, 5. 



Quadrate: Depth 32.0mm. 



Length of superior border 34.5 " 



Pachyrhizodus velox. Plate XLIX, fig. 2. 



Pachyrhizodus vclox Stewart, Kans. Univ. Quart., vol. vn, pp. 193-195. 



This species is represented by a maxilla, both mandibles, 

 fragmentary quadrate, numerous portions of branchiostegal 

 rays, and a fragment of another bone that I first described as a 

 portion of one of the hyoids. 109 I have since reached the con- 

 clusion that it must be some other part, as the bone is too much 

 contracted back of the extremity to be a portion of a ceratohyal. 

 The catalogue number of the specimen is 316. 



The maxillary is long and slender and of about equal depth 

 from the superior condyle backward. The condyle is elevated, 

 but how much cannot be determined, as the superior portion is 

 not preserved. Just beneath the condyle the bone thickens and 

 the outer surface contracts inward. External to the condyle 

 there is a broad shelf of bone which is very roughly striated. 

 The premaxillary surface is not preserved. The alveolar border 

 supports about forty-seven teeth, as near as can be estimated. 

 They are conical, directed slightly inward, and closely set. The 

 crowns present a smooth enameled surface. The whole of the 

 posterior portion of the bone is finely striated. Just above the 

 alveolar border in the anterior half of the bone there are many 

 small, nutrient foramina leading inward. 



The mandible differs from that of P. latimentum Cope in not 

 having a tooth on the symphysis within the anterior one, and 

 in having a greater depth at the coronoid with reference to its 

 length. 



109. Kans. Univ. Quart., vol. VII. p. 194. 



