102 PR0CEEDTX08 OF THE NATIONAL MUSEUM. vol.46. 



a'. Lower camassials with trenchant heel. Cuon, Lycaon. 



a?. Lower camassial with heel more or less basin-shaped with two prominent cusps. 

 6*. Heel of camassial reduced, narrower than trigonid, length contained in total 

 length of tooth about four times; main cusps of camassial heel, and an- 

 terior pair of mj as well, verj^ unequal in size. 

 c*. Protoconid and paraconid of camassial very large and full, subconic to 

 summit. Premolars robust, with but one posterior tubercle each on 

 Pj, p^, and usually on p^- Each premolar has besides a posterior basal 

 shelf formed by the cingulum. Canis (wolves and domestic dogs), 



c^. Anterior premolars greatly reduced. Epicyon (extinct). 



h^. Heel of camassial less reduced, about equaling triconid in width, length of 

 heel contained in total length of tooth three and one-half times or less. 

 Protoconid and paraconid of camassial less full and more bladelike. 

 Innercusps of camassial heel and anterior pair of m^ relatively larger, 

 sometimes almost subequal with the opposing outer cusps. 

 c^ Molars and premolars relatively narrow or compressed, 'p^ with two pos- 

 terior tubercles and basal cingulum, ^3 and usually p2 '"^^h a single 

 posterior tubercle. Canines large, but relatively longer than in the 

 wolves. Canis {Lysciscus) (coyotes). 



c2. Premolars relatively shorter as in the wolves but with higher more pointed 

 cusps. P4 with two posterior tubercles and a cingulum as in the coyotes, 

 but with no posterior tubercles on the other premolars. 



Canis aureus, etc. (jackals). 

 c*. Camassials proportionally small with relatively lower crowns, p^ with one 

 posterior tubercle and a posterior basal cingulum cusp, p2 and p^ 

 with posterior tubercles obsolete or wanting. 

 (P. Tooth cusps prominent, trenchant; heels of premolars short. 



Vulpes (red fox). 

 (F. Tooth cusps less prominent; heel of camassial broad with posterior 

 inner tubercle (entoconid) small; heels of premolars long. 



Alopex (Arctic fox). 

 c*. Camassial moderately robust with short paraconid, and long, broad heel; 

 premolars relatively long, low and simple, except p^, which has two 

 well-defined posterior tubercles and a posterior basal cingulum; canine 

 and anterior premolars relatively small, jaw of great relative depth in 

 region of camassial. Canis armhrusteri (extinct). 



In the new species from the Cumberland Cave, C. armhrusteri, the 

 general form of the camassial is more Hke that of the coyote and 

 jackal, and in the heavy three-cusped p^ combined with the relatively 

 small, simple, single-cusped p^ and f^ and small canine it resembles 

 the jackal despite its much greater size. The relatively deeper jaw 

 and broader more basinhke heel of the camassial would, however, 

 scarcely warrant considering it a member of that group. It prob- 

 ably represents an extinct group of dogs which when better known 

 may be referred to a nQW genus. 



