A New Species of Dinictis from the White 

 River Miocene of Wyoming. 



BY ELMER S. RIGGS. 



Among the specimens collected by the Kansas University 

 Geological expedition of 1895 is one of a sabre-toothed cat having 

 the general characteristics of Dinictis, but differing markedly from 

 any described species. It comes from the Oreodon beds of eastern 

 W3'oming. The distinctive characters are: The absence of the 

 second lo\ver molar, the slenderness of the base and the concave 

 outer border of the upper sectorial as seen from above and the 

 presence of but two incisors in the mandible. The name D. 

 paiicidcus, sp. nov. , is proposed for it. 



The material consists of a skull, mandible, radius, ulnaj, humeri, 

 the atlas, axis, and eighteen other vertebras, together Avith numer- 

 ous fragments. The skull is badly weathered in the frontal and 

 premaxillary region, but the lower surface, the arches and the 

 occipital portion are well preserved. The mandible is almost com- 

 plete. The teeth are all present save the incisors and the upper 

 tubercular molars. Compared with D. fclina Leidy, the type of 

 the genus, the skull is a little longer and broader across the arches, 

 but narrower across the basi-occipital region. The capacity of the 

 brain cavity is not above two-thirds as great, and the root of the 

 zygomatic process does not project below the basi-cranial axis. 

 The sagittal crest is thin and high, the arches slender, and the 

 supraoccipital is moderately projecting. The otic bulke are well 

 inflated, and the paroccipital processes slender and directed back- 

 ward. The infraorbital foramen is large, though not enough of its 

 border remains to determine its shape. The palatine foramina lie 

 opposite the anterior border of the third premolar. As in D. cyclops 

 Cope, the sphenoorbital and rotund umforamina are conjoined and 

 situated well forward. The latter receives a small ali-sphenoid 

 canal connecting it with the foramen ovale. The last foramen cor- 

 responds in position with that of D. felina as described by Scott,* 

 but is less prolonged transversely by the alisphenoid canal, which 

 opens at its inner border. The foramen lacerum medius is large, 



''Proceeclinss of the Acadepiy of Natural Sciences of riiiliiclelphia 1889. 



(3:J7) KAN. FNIV. QUAK. VOL. IV, NO. 4. APRIL, 18'.)(i. 



