484 Mr. O. P. Hay on 



ectopterygoid, pg, is defective. As I interpret the bones, the 

 arch is remarkable for the large size of the palatine, pa. 

 While the sutures which are represented in the figure are 

 very distinct, I am wholly unable to rind one separating the 

 entopterygoid, e/>, from the metapterygoid, mt.pg. On the 

 upper border of the arch, at the point indicated by the line s, 

 there appears to be an indication of a suture. If such it is, 

 it probably extends downwards to a point near the hinder 

 end of the palatine. The arrangement of the bones is quite 

 different from that found by myself in Xiphactinus*. 



At the lower border of the anterior end of the palatine 

 there is a broad surface, v, which was probably in contact 

 with an articulating surface on the vomer. The notch seen 

 in the anterior end is occupied by another articulatory sur- 

 face, mx, for the anterior palatine condyle of the maxilla. 

 The anterior end of the upper border furnished an articulation, 

 pfc, with the prefrontal, but this is elongated and rough, not 

 broad and smooth, as it is in Xiphactinus. 



Anteriorly the palatine is thick and strong. On its outer 

 surface this portion is finely vermiculated above, while the 

 lower portion furnishes a concave articulation for the condyle 

 of the maxilla. The general appearance of this portion may 

 be seen from fig. 4, which represents the palatine of the next 

 species. Below the concave surface for the palatine condyle 

 of the maxilla there is seen a broad rough surface which 

 must have been applied to the inner face of the maxilla. 

 The greater portion of this is wanting in the specimen shown 

 in fig. 4. Its limits are indicated by the dotted line. On 

 the outer face of the metapterygoid, from the highest point 

 seen in fig. 3 there runs downward and backward a sharp 

 ridge which evidently bounded the orbit below. The portion 

 of the metapterygoid above and mesiad of this ridge formed 

 the floor of the orbit. This indicates that the orbit was 

 placed well backward. I find no satisfactory evidences of 

 the presence of teeth on the pterygoid and palatine bones. 

 If we add to the maxillary the probable antero-posterior 

 extent of the premaxillary, we shall find that it is approxi- 

 mately equal to the length of the lower jaw. Hence the 

 latter did not project beyond the upper jaw as it did in the 

 case of those species which Stewart has referred to the genus 

 Saurodon. 



Two characters seem to distinguish Saurodon from Sauro- 

 cephalus, viz. : the presence of notches, instead of foramina, 

 for the successional teeth and the projection of the lower 



* Zoolog. Bull. ii. 1898, p. 39, iig. 7. 



