DII 0T1 LIN I OF IMERN A. 327 



ver, I am inclined to believe Dr.Le Conte was right in referring it to Platy- 

 gonus compressus, for the form of the fragment of face is very different from the corre- 

 sponding portion of that specimen upon which Dicotyles depressifrons was characterized. 

 Vnd farther, the premolars contained in the fragment (PI. 37, fig. 11,) have the same 

 form ami size as those just described, (PI. 37, fig. 12,) which with very little doubt be- 

 longed to the same individual as the fragment of lower jaw characteristic of Platygonus. 

 In both, the first premolar possesses but a single conical lobe, which is a very different 

 condition of the tooth as it exists in Dicotyles, or the cave head hereafter to he described. 



The fragment of a face under consideration, which most probably belongs to Platygonus 

 compressus, is constituted by portions of the superior maxillary bones, the right inter- 

 maxillary bone and a portion of the right nasal bone. It appears narrower or more com- 

 pressed laterally than in Dicotyles torquatus, arising principally from the absence of the 

 ridge so conspicuous in the latter proceeding from the inferior margin of the malar bone. 



The nasal bone is a little less convex transversely than in Dicotyles torquatus, but is 

 about as much so longitudinally. 



The crcscentic ridge of the canine alveolus rises higher relatively than in Dicotyles, 

 and in its course forwards runs into the margin of the nares. The intermaxillary bone 

 appears to be unusually long, its upper end being over three inches posterior to the sum- 

 mit of the canine alveolar ridge. Its lateral surface at the upper extremity presents di- 

 rectly outwards, but at the lower half inclines at an angle of about 50°. The upper part 

 of the superior maxillary bone about three inches posterior to the canine alveolar ridge, is 

 protuberant, but presents no indication of possessing the acute ridge proceeding from the 

 malar bone and characteristic of Dicotyles. The permanent premolars (PI. 37,fig. 11.) 

 preserved in the Bpecimen from being unworn, exhibit better their characters in detail 

 than those described. As before mentioned, they have the same size and form of those 

 just alluded to. Their basal ridge is tuberculate and foveate. The principal lobes in the 

 hinder two premolars arc confluent at the middle of their basal two-thirds. 



The hiatus between the first premolar and the canines, is about one and three quarter 

 inches. The canines have about the same decree of divergence from each other as in 

 Dicotyles, but they appear to project a little more forward. 



A d< tached upper canine tooth (PI. 37, fig. 1(h) undoubtedly belonging to the same 

 species, and having (Ik; crown perfect and but little worn, exhibits the same form, and 

 about the same degree of lateral compression as in Dicotyles torquatus. 



The hiatus between the anterior margin of the canine and the lateral incisor is about 

 ten h 



The latter tooth in the specimen is one of the permanent incisors, and it had not yet 

 entirely protruded. Its crown i.-^ but little more than half the size of that of I), torquatus, 

 ami its form is more Bimple; being shorl and slightly compressed mammillary, with the apex 

 impressed by an shaped disk, with a Blightly prominent tubercle in its centre. It i- 

 convex both anteriorly and posteriorly ; in the latter position, being concave in Dicotj les. 

 vol. \. — 59 



