86 KANSAS UNIVERSITY SCIENCE BULLETIN. 



present in the median line at the caudal extremity of the skull. 

 The post-temporal, which is so seldom found, lies at the caudal 

 end of the skull, just to the right of the occipital crest in. the 

 figure. The bone marked x is present in a few specimens, but 

 has not been observed attached to any other bone, and hence 

 has not been determined. It is probably a part of the suspen- 

 sory apparatus of the pectoral girdle. Fragments of the 

 supraclavicles are to be seen just behind the opercular. They 

 are quite slender and slightly expanded at the ventral ends. 

 The dorsal ends of both are broken off. One of these ends is 

 lying just back of the left side of the skull. Both palatines 

 are present, one of them being refigured (pi. XV, fig. 14) on a 

 larger scale to show the prominent base of a recently discarded 

 fang. The other palatine shows the bases of the discarded 

 fangs absorbed in the usual manner. This is the only indica- 

 tion, among all of the palatine fangs of the specimens of the 

 University of Kansas Museum, of an alternation in the re- 

 placement of the palatine fangs ; though specimen No. 198 of 

 the American Museum furnishes another instance. The oper- 

 cular was very large. Its outline is traced with a broken line 

 in the figure. The subopercular is represented, but is only 

 fragmentary. Its impression in the matrix furnishes the out- 

 line of this element in position. The interopecular is almost 

 complete, but does not lie in position. There is a small pro- 

 tuberance on the caudal edge of the preopercular about one- 

 third its length from the lower extremity, which is probably 

 for the articulation of the subopercular. There are no teeth on 

 the external alveolar border of the dentary. All of the teeth 

 are slightly grooved mesially. There are thirty-nine vertebrse. 

 Possibly some are missing, but certainly not more than two or 

 three. They are constricted and are irregularly grooved later- 

 ally. The caudal fin has been poorly preserved, the rami of the 

 fins being represented only by the proximal ends of the fin 

 rays. The hypural is present and in position. The bone 

 marked /, just ventral to the hypural, is an azygous bone, 

 which probably supported a fleshy fin. A much better caudal 

 fin of this species is at hand, and is described below. The 

 specimen under discussion is only about one-half the size of 

 specimen No. 803, and it is quite possible that it is distinct, 

 but since the palatine fangs are clearly of the Enchodus pet- 



