t903.] 



Hay, North Af?iertcati Cretaceous Fishes. 



from below. The outer surface of the right dentary is ob- 

 served; also the tooth-bearing and triturating surfaces of the 



•pmx. 



vom. 



premaxillse, the maxillae, 

 the palatines, the vomer, 

 and the parasphenoid. 

 The premaxillae are sculp- 

 tured with grooves su- 

 periorly and with pits 

 nearer the tooth line. 

 Here we find a band of 

 5 or 6 rows of small teeth. 

 The outer rows of teeth 

 become very small and 

 some of them are found 

 standing on the narrow 

 walls 'surrounding the 

 pits. A similar band is 



found on each maxilla, ^f^t^^J^- P--P'^-°i'i= ^"'-•' p-™--""-; 



and on each of the den- 



taries. What I regard as the parasphenoid Cope has described 

 as the vomer. It is, however, too elongated; and besides, it 

 seems to correspond with what is certainly the parasphenoid 

 in other specimens of the genus figured in this paper. More- 

 over, there is a patch of teeth farther forward which is sup- 

 posed to belong to the vomer. Cope has spoken of this 

 parasphenoid as if it were covered with small teeth. I find 

 traces of teeth around its border and a considerable patch in 

 front; elsewhere, the bone is occupied by pits and is devoid 

 of teeth. Where the teeth are very small, they occupy the 

 summit of the bone surrounding the pits. This bone, as 

 well as the palatines, is thin, only about 2 mm., but this is 

 probably due to pressure. The pits have the appearance 

 of passing deeply down into the mass of the parasphenoid. 

 The surface of the dentine-like layer of the bone presents 

 evidences of wear. The lower surface of the palatines re- 

 sembles the surface of the parasphenoid. A few small 

 teeth are to be seen around the borders of the bone. 

 The patches of teeth between the maxilla and palatine 



