242 MEMOIRS OF THE UNIVERSITY OF CALIFORNIA. 



orbital foramen is situated a little lower than in the larger specimens from 

 Rancho La Brea. 



Comparison with Cope's Texas Specimen. The material which Cope de- 

 scribed from the Texas Pleistocene includes very little on which to base a 

 comparison. Fortunately the first upper molar (pi. 25, fig. 5), which is the 

 most characteristic tooth in the whole dental series of C. dims, is represented. 

 The dimensions of this tooth, as nearly as can be determined from Cope's 

 figure of the specimen, are near to those of the type and to those of the Cali- 

 fornia specimens. The general form of the tooth is clearly similar to that of 

 both the type and the California material in the essential characters. The 

 hypocone is greatly reduced, and the protocone is of moderate size, while the 

 paracone and metacone are rather large. According to Cope's description 

 and figure, the alveolus of the antero-internal root of the superior carnassal 

 extends far forward so that its anterior border overlaps the posterior third of 

 P 3 . Such a form in this root has not been exactly duplicated in the California 

 material, although it is suggested in one specimen. If it is normal it would 

 probably constitute a valid character distinguishing the Texas form. It 

 is conceivable that the form of root seen here is abnormal. It seems quite 

 unnecessary unless the deuterocone were very largely developed, and since 

 the hypocone of M 1 is much reduced and the crushing power weak it is not 

 probable that the deuterocone of P 4 was unusually developed. 



Cope noted that the Texas specimen differed from Leidy's type in the fol- 

 lowing particulars: P 3 distinctly longer and the external cingulum weaker: 

 internal root of P 4 extended farther forward ; protocone of M 1 less conic than 

 in the type and external cingulum of M 1 weaker. He suggested that the differ- 

 ence in the external cingula might be due to age, and was inclined to consider 

 the two individuals as representing the same species. 



In Cope's figure of the Texas specimen 16 there is a suggestion of a break 

 at the postero-external angle of M 1 , which has carried away the cingulum 

 at this point. If this is the case, the anteroposterior diameter of M 1 would be 

 shortened, and the length of P 3 would appear relatively large. The character 

 of the external cingulum is found to be quite variable in the Rancho La Brea 

 series of specimens. The nature of the antero-internal root of P 4 has been 

 referred to above by the writer. The slight difference in the degree of lateral 

 compression of the protocone of M 1 is fully equalled among the individuals 

 of the Rancho La Brea series. 



So far as evidence is available, there seems to be good reason for consider- 

 ing the California and Texas forms as closely related, if not identical species. 



Comparison with Material from Sheridan Formation. A specimen in the 

 collections of the American Museum which was obtained in the Sheridan forma- 

 tion of Kansas evidently represents Canis dims. It consists of a lower jaw 



i Cope, E. D., Jour. Acad. So. Philad., ser. 2, vol. 9, pi. 21, fig. 15, 1895. 



