MERRIAM: THE FAUNA OP RANCIIO LA BREA. 



231 



specimen 



9 10 



Figs. 8 to 10. (!<ini.t ilinis Lciily. M 2 , 

 superior view, natural size. Fig. 

 8, no. 19472; fig. 9, no. 19473; fig. 

 10, no. 19474. Kancho La Brea 

 Beds. 



and transversely in comparison with the inferior carnassial. In 

 10856 M 2 shows an anteroposterior diameter of 

 12.8 mm., in comparison with 35.7 mm. in the car- 

 nassial. In the large Alaskan wolf, ('. /xniibasileus, 

 (no. 984, Univ. Calif. M.us. Vert. Zool.) the corre- 

 sponding dimensions are M 3 , 12 mm.: carnassial 

 29 mm. In M :) the relative reduction is still more 

 noticeable, this tooth measuring 7 mm. anteropos- 

 teriorly in the C. pambasileus specimen and only 

 6.5 mm. in C. dints (no. 10856). The reduction in M 2 is due in some cases to 

 a noticeable weakness of the heel region. The metaconid of M 2 is in some 

 cases reduced to a small tubercle situated on the side of the nearly central 

 protoconid. In rare cases a small tubercle is present in the paraconid region 

 (fig. 8). As a rule no tubercle is present to represent paraconid or parastylid 

 (fig. 10). 



A very large specimen (no. 11281) referred to C. dims presents a number 

 of characters in which the dentition varies slightly from the typical individuals 

 of this species. (See fig. 11). At the same time the principal peculiarities of 

 this specimen are those of the C. dims form. P 4 is exceptionally massive, the 

 transverse diameter of the protocone blade 

 being relatively large. Another even larger 

 upper carnassial with an anteroposterior 

 diameter of 35.2 mm. (no. 12576) is relatively 

 a little thinner transversely. In M 1 of speci- 

 men 11281 the hypocone is larger than in any 

 other individual found. It does not, however, 

 reach the relatively large size of the Recent 

 American wolves, nor is the hypocone ridge 

 extended around the anterior side of the protocone as in the wolves of the C. 

 occidentalis type. In M 2 also the hypocone is relatively a little larger than in 

 the average of the Rancho La Brea individuals of C. dims. The metacone is 

 also relatively a little larger than in average specimens from this locality, 

 having, as in Leidy's type, nearly the size of the paracone. 



A lower carnassial associated with no. 11281 also indicates an individual of 

 gigantic size. The characters of this tooth are those of the typical C. dims. 



Specimen 11281 evidently belongs in the true C. dims group, but represents 

 an exceptionally large form varying from typical individuals in the nature of 

 the hypocone of M 1 . 



Fig. 11 Canis dirus Leidy Upper carnassial 

 and upper molars, occlusal view, no. 

 11281, natural size. Rancho La Brea 

 Beds. 



