40 



The mental turiiincii is siiiallcr tliaii in (ho tapir, and is .situated l)el()\v the 

 interval of the second and third picniolars 



The length of the lower jaw, fi-om its back border to the fore part of the 

 second premolar, is [)'\ inches, and in the complete condition it measured 

 about 2 inches more. 



Portions of several lower jaws, apparently all referable to Palseosyops, were 

 ol)tained by Dr. Corson at Grizzly Buttes. The specimens exhibit some 

 variation in character, and may, perhaps, belong to more than one species of 

 the genus. One of the specimens consists of a dentary fragment containing 

 (he true molars and the fangs of the two premolars in advance. The retained 

 teeth are like those previously described, but are in a trifling degree smaller. 

 The series measures 3| inches. The jaw-fragment nearly agrees with the 

 corresponding portion of the specimen above described, but is of more uniform 

 depth. 



Another specimen consists of a right ramus, without the chin and back 

 part, and broken into three pieces. It contains the fang of the canine and 

 most of those of the molars. The jaw is of more uniform depth below the 

 position of the teeth than in the more complete specimen first described, and 

 more robust than in cither of the former specimens. The retained portion 

 of the fang of the canine indicates a larger tooth than existed in the first- 

 described specimen — one, also, that would accord in its robust character with 

 those of the facial specimen referred to Palceosijops iJcdudosus. The presence 

 of the fang of the canine produces a strong bulge at the side of the chin, 

 which apj/cars to have been comparatively feeble in the first-described speci- 

 men. Two mental foramina are situated below the position of the second 

 and third premolars. The first premolar appears to have had a single fang 

 consisting of a connate pair. It was separated from the canine and second 

 premolar by conspicuous intervals, the posterior of which is the larger. A 

 ])ortion of the chin being retained in the specimen, it would a})pear in the 

 entire condition to form a broad slope defined at the sides liy the convexities 

 of the canine alveoli. The rami were completely co-ossified at the symphysis 

 witiiout the suture of union being apparent. 



The remaining specimen consists of a portion of the jaw containing the 

 limgs of the last two molars, and the portion immediately jjehind extending 

 toward the angle. The dentary portion of the bone is considerably deeper 

 (hau ill (he corresponding portion of Ihe preceding specimens. The l)ase 



