217 



margin ; and, between the latter and the scries of foramina, the surface is 

 slightly convex and minutely rugose. 



Measurements. 



si. 



Depth of the bono - 0.035 



Thickness at the rugose band - - 0. 0055 



Total length of a tooth (?) : 0.02 



Length of a crown '- - 0. 004 J 



Width of a crown 0.0030 



Number of teeth in one inch, 8. 



The size of this fish was probably about equal to that of the Iclithyodectes 

 anaides above described. 



The type-specimen was found loose on a bluff of blue shaly limestone, 

 fifteen miles south of Fort Wallace, Kansas. 



ERISICHTHE, Cope. 



Proceedings of the Academy of Philadelphia, 1872, p. 280. 



In this genus, the teeth are implanted in deep sockets as in other Sauro- 

 dontidce, and the subalveolar line of foramina seen in Sauroceplialus is wanting. 

 The crowns of the teeth are compressed and knife-like, as in Daptinus; but 

 those of the anterior parts of the dentary and maxillary bones are greatly 

 enlarged. Maxillary bone short, and rapidly tapering to a narrow edentulous 

 extremity. Gi - eater part of the dentary with a rugose band on the inner 

 side of the teeth; its distal portion with a row of small compressed teeth, 

 separating the large teeth into two areas. 



While this genus agrees with Portheus and Ichthyodectes in the absence 

 of nutritious dental foramina on the inner face of the dentary bone, and 

 especially with Portheus in the irregular sizes of the teeth, the crowns are 

 compressed and knife-like, and closely similar to those of Sauroceplialus. 

 But the form of the maxillary is so different from anything known among 

 Saurodontidce as to render it probable that the genus pertains to another 

 family-division. 



The Portheus angulatus, Cope, from North Carolina, perhaps belongs 

 to the genus Erisichthe, differing from E. nitida in its greater size and less 

 degree of compression of the crowns of the large fangs. 



Erisichthe nitida, Cope. 

 Represented by numerous portions of a cranium with a fragment of a 

 pectoral ray, discovered by Prof B. F. Mudge near the Solomon River, 

 28 c 



