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lines in length to its bifurcation at the forehead. The temporal surfaces 

 appear to be full and convex, as in the weasel. 



An occipital condyle resembles those of the latter, and measures about 4 

 lines in its longer diameter. 



The ramus of the lower jaw, compared with that of the weasel, is more 

 slender and delicate in its proportions. In the specimen both extremities 

 are broken, but a portion of the symphysis is still retained. 



The jaw below the molars is of nearly uniform depth, and measures about 

 2 lines. The base is slightly convex fore and aft, but makes a concave turn 

 toward the angle. The masseteric fossa below is well marked. A small 

 mental foramen occupies a position below the antepenultimate premolar. 



In the earlier description of the specimen, I remarked that seven molar 

 teeth, in an unbroken series, appear to have occupied the side of the jaw. In 

 the actual condition of the fossil there are four teeth, consisting of the anterior 

 two molars and the two premolars in advance. In front of these there are 

 two empty sockets and parts of two others, and behind them there are the 

 imperfect alveoli for a third molar. The sockets at the front of the jaw I at 

 first supposed were intended for two additional two-fanged premolars. They 

 fill up the interval between the retained teeth and the edge of the symphysis 

 so closely that, from this fact and their relative size, I now suspect that they 

 may have been occupied by a single-fanged premolar, a small canine, and 

 two incisors. Assuming that such was the case, without any certainty in the 

 matter, the number of molar teeth in the series would be six, of which three 

 were premolars and three true molars. In this view the teeth retained in 

 the specimen consist of the second and third premolars and the first and sec- 

 ond molars. Their constitution would appear to indicate an insectivorous 

 animal which, perha'ps, was marsupial in character. 



The teeth successively decrease in prominence or height from the second 

 premolar to the second molar. They resemble in constitution the corre- 

 sponding teeth of the opossum. 



The crown of the premolars is laterally compressed conical, thicker behind 



than in front, and is embraced by a basal ridge. The crown of the second 



premolar, more prominent than in any of the other teeth, is triangular, longer 



than broad, and sharp-pointed. Its anterior slope is slightly convex and acute; 



its posterior slope is longer, slightly concave, and wide. The basal ridge 



forms an excavated heel behind, a more elevated ledge in front, and a pair of 

 16 G 



