302 



University of California Publications. 



[Geology 



AFFINITIES. 



Relation to Felis atrox Leidy. — The lower jaw of the Rancho 

 La Brea specimen approaches very closely in measurements the 

 peculiar feline jaw from Natchez, Mississippi, which served as 

 Leidy 's type of Felis atrox. Leidy 's original specimen unfor- 

 tunately consisted of only a half of a lower jaw with the cheek 

 teeth and the canine. The comparable dimensions are surpris- 

 ingly close, particularly in the case of the cheek teeth, as is shown 

 in the table of measurements (p. 300). The cheek teeth are sim- 

 ilar in the lack of elevation of the cusps, and in the form of the 

 cusps of P 4 . The principal differences are found in the slightly 

 longer anteroposterior diameter of the canine, in the greater de- 

 velopment of the anterior basal tubercle of P 3 , the shorter dias- 

 tema, and possibly the greater development of the anteroinferior 

 portion of the symphyseal region, in the Rancho La Brea speci- 

 men. Slight differences may also exist in the reduction of the 

 posterior basal tubercles of M 1 in the type specimen. This char- 

 acter is, however, always more or less variable. 



Mr. Witmer Stone, who has kindly examined Leidy 's type 

 for me, finds a slight indication of an interior basal tubercle on 

 P 3 of the type, though it is not shown in Leidy 's figure. This 

 character is more or less variable in the lion. 



The form of the mandible is not certainly to be depended 

 upon for specific diagnosis, as the type specimen Avas covered 

 with a thick ferruginous coating, which may be supposed to 

 have disguised its form somewhat. The marked prominence 

 represented on the inferior border of the jaw below the anterior 

 end of P 4 in Leidy 's figure, and considered by Dawkins and 

 Sanford 5 as a possible ramal process, is probably to be consid- 

 ered as principally an irregularity of the ferruginous coating of 

 the jaw. Mr. Witmer Stone, who examined the type with refer- 

 ence to this feature, states that "it has been much exaggerated 

 in the figure, or has been removed since. ' ' Mr. Stone believes 

 that it was without question part of the matrix. 



The form of the symphyseal region in the Rancho La Brea 



5 British Pleistocene Mammalia, part 3, p. 161. 



