84 KANSAS UNIVERSITY SCIENCE BULLETIN. 



vertical lamina, which pi'obably joins a corresponding lamina 

 on the pterygoid. On the dorsal surface, about one-third its 

 length from the cephalic end, is a deep groove, oblique to the 

 axis of the palatine, in which the lateral processes of the 

 ethmoid articulate. The enlarged caudal end of the para- 

 sphenoid is missing. The ventral view shows the angle of 

 compression of the palatine fangs. There are two cutting 

 edges, one directed outward and one cephalad, the mesio- 

 caudal surface being rounded and the proximal half of this 

 surface strongly grooved. The measurements of this speci- 

 men are as follows : 



mm. 



Cephalo-caudal measurement of opercular .■ 73 



Length of the palatine fang- 45 



Width of caudal end of skull 90 



Length of bar on mesial side of opercular 45 



Figures 2, 6, 7, and 9, plate III, represent another specimen 

 of Enchodus petrosus, No. 803. Palatines of several other 

 individuals are shown on the same plate for comparison. The 

 upper figure of figure 5, and the small specimen, figure 11, 

 may not be E. petrosus. The extent of the grooving on the 

 postero-internal surface of the fang is shown in figure 3, 

 specimen No. 833; also just above this tooth is shown a cross 

 section taken about the middle of the fang. The pterygoid 

 ipt, fig. 9) is found to be a stout bar bearing nine teeth. One 

 is a very large, laterally compressed tooth, and the others are 

 represented only by bases. The most cephalic of these bases 

 stands at the front end of the bone. Just caudad to this base 

 is another which has begun to be absorbed. The large tooth 

 has a cephalic cutting edge, but the caudal edge is sharp for 

 only about two-thirds of the distance from the distal end. A 

 line drawn in the long axis of the cross section of this tooth 

 would pass external to the palatine fang about twenty-five 

 millimeters. The tooth is grooved mesio-caudally. Caudally 

 the quadrate bears a deep groove for the reception of a cone- 

 shaped process on the cephalic edge of the ventral end of 

 the preopercular. The quadrate has a strong articulation with 

 the articular. The appearance of the mesial surface of a 

 mandible of this species is shown in figure 8, plate III, and 

 the external surface is shown in figure 9 of the same plate. 

 The bases of the teeth caudad to the dentary fang are slightly 

 swollen. This can not be shown, since there is a thin plate 

 of bone along the external alveolar border. There is no fringe 



