430 H. GOVIEE SEELEY ON THE OCCURRENCE OF 



ridge is much, more developed; the anterior and posterior halves 

 of it do not meet. Above this tooth the outer bone of the jaw 

 thickens into a fold. 



The fifth tooth is imperfectly preserved ; it appears to be shorter 

 than the others, somewhat thicker, with the denticles a little better 

 marked. 



The teeth were inclined towards each other from both sides of the 

 snout, and locked between those of the lower jaw. 



There was found with the specimen a remarkable single-fanged 

 tooth, which may be one of those missing from the empty sockets. 

 This tooth resembles the canine tooth of a Carnivore. It is longitu- 

 dinally ovate in section, and in length recurved, with a tapering 

 crown and a fang which continues to enlarge for some distance below 

 the crown and then contracts somewhat towards the base. The 

 extreme end of the fang is broken away, while its whole lower part 

 has been greatly fractured and somewhat crushed. The extreme 

 length of the portion of the tooth which is preserved is 2-J inches, of 

 which the crown covered with enamel constitutes 1 inch. The base 

 of the crown from back to front, where the enamel terminates, 

 measures f- inch, and from side to side in the same line it measures 

 less than -A- inch ; the crown is more compressed from side to side 

 in front than behind ; and while the anterior margin, in common 

 with the outline of the whole tooth, is convex, the posterior margin 

 in the same way is concave, but with a curve which belongs to a 

 much larger circle than that of the anterior margin. Along these 

 anterior and posterior margins on the crown runs an elevated ridge 

 of enamel. The ridges do not extend over the point of the crown, 

 which is blunt, rounded, and unworn. On the sides of the crown 

 and towards its base the enamel, which nowhere has a burnished 

 smoothness, but an exceedingly fine subgranular shining texture, 

 becomes wrinkled into sharp short vertical folds, which are more 

 numerous on the back than on the front aspect, and may number 

 about a dozen on each side of the tooth. They are fine, irregular, 

 not straight; and sometimes two converge and unite into one in 

 passing up the crown. The fang where widest measures J inch 

 from front to back. Like the crown, it is more compressed from 

 side to side on its convex than on its concave side. It is marked 

 throughout with exceedingly fine longitudinal striae ; and at intervals 

 among these are faint ridges which are prolongations downward of 

 the chief ridges on the crown. The pulp-cavity is large. 



This form of tooth would yield one of the best distinctive charac- 

 ters for the species. 



The Parietal Bone. 



The parietal bone, which is single, has the form usual in Zeuglo- 

 donts, as far as can be judged from the fragment preserved, though 

 various small pieces collected with it probably indicate that the 

 parietal region was longer in this animal than in the American 

 Zeuglodonts. The anterior suture, with the adjacent part of the 



