FREE INSTITUTE OF SCIENCE 



UINTA SELENODONTS J 



width throughout, because the inner or lingual borders of the premolars 

 and molars are arranged in almost the same fore-and-aft lines, those of the 

 two sides keeping nearly parallel. However, the total breadth of the skull, 

 measured to the outer sides of the teeth, is far greater at m^ than at p- 1 -. The 

 palate is narrowed in front of p 3 -, but broadens again slightly at p 1 and still 

 more at the canines. Anteriorly the palatine plates diverge widely to receive 

 the premaxillary spines. The posterior nares are not preserved in either of 

 the available specimens, but enough is left to show that the opening must 

 have been farther back than in Leptoreodon, and that the palatal notch, which 

 is quite distinct in the latter, is hardly at all indicated. This character of the 

 palate forms another approximation to the structure of Leptomeryx. 



Comparatively few of the cranial foramina are exposed to view. The 

 condylar foramen is large and is placed in the angle between the condyle and 

 the horizontal portion of the basioccipital ; external to it is a second small 

 foramen. The foramen lacerum posterius is a narrow, curved slit, which 

 bends around the periotic and is continued anteriorly into the foramen 

 lacerum anterius, though the bulla probably separated them when it was 

 present. A large glenoid foramen makes a conspicuous opening upon the 

 hinder face of the postglenoid process. As in Lcptomeryx, the foramen 

 rotundum is separate from the foramen lacerum anterius and is placed near 

 the foramen ovale, internal to the glenoid cavity. A small venous foramen 

 perforates the bony palate on each side, opposite p 1 . The infraorbital fora- 

 men, which is quite large, occupies the same position as in Leptomeryx, 

 opening above p— and well in advance of the orbit. I can detect no supra- 

 orbital foramen, but the frontal is not sufficiently complete in either of the 

 specimens to enable me to say definitely that it was lacking. If present, 

 however, it must have held a very different position from that of Leptoreodon, 

 farther forward and much nearer to the median line ; the absence of vascular 

 grooves on the forehead is a marked distinction from Leptoreodon and Oro- 

 meryx. In Leptomeryx the supraorbital foramen is a minute paired opening 

 placed near the outer rim of the frontal. 



In the collection of the American Museum of Natural History is a speci- 

 men (No. 2070) which apparently belongs to this genus, though in the un- 

 fortunate absence of upper teeth the reference must remain somewhat uncertain. 

 The cranium agrees exactly both in size and in character with that of the 

 type specimen, and this agreement is the principal reason for referring the 

 fossil to Ccimelomeryx. 



