228 MEMOIRS OF THE UNIVERSITY OP CALIFORNIA. 



minute basal tubercle on the lateral side. I 3 is not materially different from 

 the corresponding tooth in the modern wolves. 



The superior canine seems to be relatively short in anteroposterior diameter 

 at the upper margin of the enamel, its diameter slightly exceeding that of 

 considerably smaller specimens of the Alaskan wolf. The transverse diameter 

 or thickness is relatively large, and the tooth shows a more nearly circular 

 cross-section. The anterointernal enamel ridge usually runs nearly straight 

 up to the margin of the enamel, without turning backward as in Recent Alaskan 

 wolves. 



P 1 is sometimes smaller in anteroposterior diameter than P 1 of the large 

 Recent wolves. 



P" is relatively much smaller compared with the sectorial than in the large 

 Alaskan wolves, the anteroposterior diameter being about one-half that of P\ 

 This tooth is frequently almost simple-crowned, as is exemplified in no. 10856, 

 in which there is only the merest trace of a tubercle on the posterior border of 

 the cingulum. In other cases (no. 10893) there is a distinct posterior basal 

 cusp, and behind it a posterior basal tubercle. 



P 3 is also relatively small compared with the sectorial. (Ratio of antero- 

 posterior diameter in P 3 and P 4 19:32 in G. dirus no. 10856, and 16.5:24.5 in 

 a C. pambasileus from Alaska). There is a distinct posterior cusp present, 

 and a very small basal tubercle is usually developed on the posterior border 

 of the cingulum. The small posterior basal tubercle seems to be present more 

 frequently than in the Recent wolves. The protocone is in general not made 

 relatively smaller than in the Recent species through the regular addition of 

 the posterior basal tubercle. The protocone commonly tends to be relatively 

 la rge anteroposteriorly . 



P 4 is relatively large compared with all of the other premolars. The blade 

 is massive, though not much thicker transversely in relation to the size of the 

 skull in general than in the Recent wolves. The deuterocone is usually small, 

 and the root supporting it does not ordinarily project as far toward the median 

 line as in the modern wolves. Though usually distinctly set off from the pro- 

 tocone, the deuterocone is in some cases entirely reduced. 



A peculiar feature appearing in quite large percentage of the specimens is 

 found in the development of a sharply angular ridge on the lower side of the 

 cingulum on the outer side of the tritocone. The character of this ridge is 

 in general similar to that of the lower side of the cingulum on the outer side 

 of the upper molars. In one instance (no. 10830) this ridge is very largely 

 developed on the left P\ and several distinct, rounded tubercles have arisen 

 upon it. This last instance may possibly be attributed to pathological changes 

 or to injury. It presents an interesting tendency of development, though it may 

 have been stimulated by extraordinary conditions. 



M 1 is relatively small both anteroposteriorly and transversely compared 



