Cope.] 70 [ Nov . is, 



Measurements. M. 



Width of crown of first tubercular 0065 



Depth of ramus at P. M. 2 024 



" "at sectorial 028 



Thickness " " 010 



Canis cusvigerus, sp. nov. 



This peculiar species is indicated by the greater partof the cranium with 

 dentition, to which are united both rami of the lower jaw with nearly all 

 of the teeth in place. These indicate a dog of small size, about equaling 

 the Canis gregarius Cope, but one presenting marked characters. 



The third premolar tooth in both jaws differs from the corresponding one 

 in the C. gregarius and in most recent species, in lacking the lobe of the 

 posterior cutting edge, agreeing in this (as regards the inferior series) 

 with the Temnocyon altigenis. It is present in the fourth inferior premo 

 lar, which has besides, a low heel. The inferior sectorial tooth is charac- 

 terized by its great robustness ; the internal median tubercle is much ele- 

 vated, while the principal cusp is short. The heel is wide and basin-shaped, 

 with the inner border as much elevated as the outer. The first tubercular 

 molar is characterized by its width as compared with its length being nearly 

 as wide transversely as fore and aft. It has two anterior cusps followed 

 by a basin with elevated borders simulating two posterior cusps. There 

 are an anterior and a exterior cingulum. The second tubercular is a min- 

 iature of the first, differing in the more robust external posterior cusp, and 

 the absence of external basal cingulum. There are no complete cingula 

 on the external bases of the other inferior teeth. The second superior 

 tubercular is well developed, having two external tubercles. The anterior 

 inner cusp of the superior sectorial is distinct and acute, and there is a 

 cingulum along the inner base of the crown. The exserted portion of the 

 canines is long, slender, and with an oval section narrowed behind. The 

 enamel of all the molars is more or less rugose, a character which is only 

 found among our extinct dogs in the 0. geismarianus. 



The mandibular rami are shallow, and their inferior margin is not stout. 

 A gentle elevation of the latter commences below the first tubercular tooth 

 and the alveolar border rises but little behind. The masseteric fossa is deep 

 and well defined. 



Measurements. M. 



Length of inferior molar series 041 



" bases of four premolars 023 



base of second " (105 



Elevation crown " " 005 



Length of base of fourth " 0072 



Elevation of crown " " 0055 



Length of base of sectorial 010 



Elevation of principal cusp 006 



Width of heel of sectorial 006 



