Species o/Saurocephalus. 485 



jaw beyond the snout of the fish. I have been inclined to 

 believe that the presence of these two characters is sufficient 

 to distinguish Saurodon as distinct. However, I observe 

 in some specimens of this supposed genus that some of 

 the notches become closed into foramina; and we can easily 

 imagine all gradations between notches and foramina high 

 above the alveolar margin. Moreover, it is probable that 

 the other character will fail. Recently Mr. Stewart * has 

 published figures, without description, of remains which 

 he refers to Cope's Saurodon phlebotomus. Mandible and 

 maxilla are shown. Measurements show that the maxilla, 

 without the premaxillary, is nearly as long as the alveolar 

 border of the mandible, so that it is almost certain that in 

 this species there was no projection of the dentary beyond 

 the snout. It seems probable, therefore, that Saurodon must 

 be abandoned. 



I present here (fig. 5) the right maxilla and the pre- 

 maxillary (fig. 4) of another species of Saurocephalus, which 

 1 regard as yet undescribed. It is especially distinguished 

 from described species by its elongated maxillary bone. To 



Fig. 5. 



illustrate this, I compare it with Mr. Stewart's S. dentatus, 

 which is itself a species with a rather long maxilla. In 

 S. dentatus the total length of the maxilla is 142 millim., 

 its height at the palatine condyle 48*5 millim. My specimen 

 has the same height at the condyle; but the total length 

 is 172 millim., a difference of 30 millim., equal to 21 per- 

 cent, of the shorter maxilla. My species, therefore, probably 

 had a relatively slender head and a larger mouth than had 

 S. dentatus. 



In the maxilla figured I count alveoli for thirty-seven 

 teeth; but in the maxilla of the other side, sumewhat broken, 



* Kan. Univ. Quart, vii. pi. xvi. figs. 4, 5. 



