464 



University of California Publications in Geology [Vol. 11 



The Mohave form is distinguished from Tephrocyon rurestris and 

 T. hippophagus by the smaller, more slender teeth. From T. Jcelloggi 

 it differs in the relatively larger M a , smaller M 2 , and smaller meta- 

 conid in M x . M 1 in the Barstow specimen measures 17 mm. in antero- 

 posterior diameter as compared with 9 mm. in anteroposterior diameter 

 in Mo. In T. kelloggi the anteroposterior diameter of 

 M 1 is 15 mm. ; of M 2 , 10.5 mm. There is a small hypo- 

 conulid on the heel of M 1 in the Barstow specimen, 

 while in the type of T. kelloggi this tubercle is not 

 suggested. The heel of M 2 seems somewhat shorter 

 than in T. kelloggi. 



P 4 and P 3 both possess a posterior cusp and a post- 

 erior basal tubercle. P 4 shows a small anterior basal 

 tubercle. The anterior side of P : . is not preserved. 



Several specimens of mandibles slightly larger than 

 no. 19402 represent a Tephrocyon species from the 

 Barstow beds very near T. temerarius. It is possible 

 that they belong to another species, but age and sex 

 are presumably competent to account for the differ- 

 ences. 



A portion of an upper jaw, no. 21512, with M 1 and 

 M 2 imperfectly preserved (fig. 8) shows a form of 

 molar teeth near that in T. rurestris, the type species 

 of Tephrocyon. A portion of an upper jaw, no. 21513, 

 with fragments of the premolars also suggests the 

 characters of Tephrocyon. 



Fig. 8. Teph- 

 rocyon, near 

 rurestris (Con- 

 don ) . M 1 and 

 M 2 , no. 21512, 

 occlusal view, 

 natural size. 

 Barstow M i o - 

 cene, Mohave 

 Desert, Califor- 

 nia. 



Fig. 9. Canid, 

 sp. small. Frag- 

 ment of man- 

 dible, no. 19463, 

 lateral and dor- 

 sal views, X 

 Barstow Mio- 

 cene, Mohave 

 Desert, Califor- 

 nia. 



AELUEODOX, near WHEELEEIANUS Cope 



Several mandibles in the collection from the 

 Barstow represent large, heavy-jawed canids of the 

 Aeluroclon type (figs. 10 and 11). Unfortunately no 

 one of the several specimens shows the dentition well 

 enough to permit a fully satisfactory comparison with the described 

 material. In general the characters of these specimens are, however, 

 quite close to those of A. wheelerianus described by Cope from the 

 Upper Miocene of the Santa Fe region. 



In forms of the type seen in no. 19398 (fig. 10) the mandible is 

 very thick and massive ; the heavy teeth are closely spaced, with a 

 tendency to be set transverse to the long axis of the jaw, there is 

 almost no diastema, the roots of the premolars are very thick, and M 2 



