106 Annals of the Carnegie Museum. 



meets the maxillary at the posterior termination of the border of the 

 air-sinus. A short distance in front of the fronto-nasal suture the 

 nasal is suddenly depressed. Anterior to this depression the bone is 

 broken off and lost, but is indicated approximately correctly by a 

 dotted line (See PI. XUII, Fig. i). The anterior palatine foramen 

 appears to be .of large size. The palatines are not well preserved, 

 while the zygomatic arches and the base of the skull, except the de- 

 tached occipital condyles, are entirely wanting. In the region of the 

 orbit the skull is much mutilated. 



The superior incisors are subequal in size, slightly spaced, and their 

 crowns are broad and somewhat fan-shaped. The diastemata in front 

 and behind the superior canine are well indicated in the accompanying 

 illustrations. The small size of the canine, which may be a sexual 

 feature, is also plainly seen in the illustration cited above. P- is 

 much reduced, its crown rather simple, and it is inserted by a single 

 fang. The rest of the premolars have a single internal cone (deuter- 

 ocone), except P^, which appears to have a slight indication of two 

 internal tubercles on the worn surface. The ectoloph of these teeth 

 is dixided into four vertical ridges consisting of the external tubercles 

 and the anterior and posterior styles, while directly anteriorly and 

 posteriorly, there are well-developed basal cingula. 



The cross-crests of the molars are quite perfect, rather sharp, and 

 directed inward and backward. The metacone is very characteristic, 

 presenting a flat external face, thus forming a cutting lobe, which 

 extends from the protoloph backward, even with the posterior face 

 of the tooth. The paracone is more convex externally. The para- 

 style is rather small and quite sessile on the antero-external angle of 

 the metaloph. There are well developed cingula directly anterior 

 and posterior, while internally there are no cingula on proto- or hypo- 

 cones. At the internal exit of the median valley there is a blunt style, 

 and on the ectoloph, especially on M-3- and M^, there is a smaller st3'le 

 located between the para- and metacones.'^'* 



The lower jaw also presents a number of tapiroid features. The 

 inferior border is quite convex fore-and-aft. The vertical ramus in the 

 region of the coronoid process is also directed well forward, and the 

 temi)oral fossa is deep. The horizontal ramus is, however, somewhat 



"■' Prof. Marsh mentioned this externally located small tubercle and regards it 

 as a specific character differentiating from Helaletes nanus. A very careful examina- 

 tion of the type of the latter reveals an even smaller tubercle similarly located. 



