87 



considerably elevated from an increased protrusion of the fang, such as is 

 observable in carnivorous animals past maturity. The fang is gibbous and 

 feebly curved. 



The molar teeth, represented in Fig. 37, magnified two diameters, are con- 

 siderably worn in the specimen, all of them exhibiting exposed tracts of den- 

 tine, due to the wear of mastication. 



The four premolars successively increase in size, and are inserted by a pair 

 of fangs, except the first, in which they appear to have been connate. The 

 crowns of the premolars from behind forward exhibit a successive reduction 

 to a simpler form from that of the molars,. 



The crowns of the second and third premolars, and no doubt also that of 

 the first one, which is lost from the specimen, have the conical form of the 

 corresponding teeth in carnivores, though they appear less prominent, due to 

 their worn condition. They are slightly thicker behind than in front, and a 

 basal ridge internally forms a slight offset or heel posteriorly, and a still feebler 

 one in the third premolar anteriorly. 



The crown of the fourth premolar is intermediate in character with those 

 in advance and those of the molars behind. Its fore part consists of a conical 

 lobe like the crown of the anterior premolars ; its back part is a broad heel 

 corresponding with the back lobe of the molars. The summit of the princi- 

 pal lobe is extended obliquely inward and backward and is continuous with 

 the inner basal ridge of the crown. Externally' the latter is embraced by a 

 basal ridge. 



The crown of the second premolar is worn away along its posterior slope ; 

 the crown of the third to a greater degree in a corresponding position, and 

 also to a less degree along its anterior slope. 



The molars are nearly alike in form and constitution, and are inserted with 

 two fangs. The crown of the molars bears a certain degree of resemblance 

 in construction to those of the raccoon, and in a Jess degree to those of the 

 opossum, but certainly enough resemblance to both to indicate a relation 

 which is not merely accidental. 



In the unworn condition of the lower molars of Notharctus, the crown 

 would appear to be composed of two divisions. The anterior division pre- 

 sents three prominent points continuous in an acute crescentoid ridge. The 

 principal point is central and external, the second is nearly as well developed 

 and internal, and the third point, feebly developed, occupies the fore part of 



