164 University of California Publications in Geology [Vol. 7 



than in the living species, but there is such variation in the 

 measurements, dependent upon age and sex, that such slight 

 differences hardly seem a sufficient ground for even subspecific 

 separation. It seems rather remarkable that L. calif omicus, 

 which is so abundant among the Potter Creek Cave rodents, 

 should not be represented in Samwel Cave. 



LEPUS A. KLAMATHENSIS (Merriam, C. H.) 

 This form of the varying hares is represented by four man- 

 dibles from Potter Creek Cave. Eleven mandibles and a portion 

 of a skull with the left upper tooth row, except for P 3 , and the 

 anterior root of the zygomata are known from Samwel Cave. In 

 size these specimens might be confused with Sylvilagus auduboni, 

 but there are distinctive differences that make their determina- 

 tion fairly certain. In the mandible of L. a. klamathensis the 

 inner point of the posterior columns of the lower molars curves 

 away from the anterior column, while in S. auduboni the two 

 columns are practically parallel, and in addition the angle is 

 sharper and begins farther back in L. a. klamathensis than in 

 8. auduboni. Furthermore, in L. a. klamathensis with age a ridge 

 develops on the outer side of the anterior root of the zygomata, 

 which is not so pronounced in S. auduboni. 



SYLVILAGUS AUDUBONI (Baird) 

 Nine specimens from Potter Creek Cave and seven from 

 Samwel Cave, all mandibles except two, a right and left upper 

 jaw without teeth, are referred to this species. It is possible that 

 these are young specimens of L. klamathensis, but they would-be 

 extremely young to be as small as they are, and the teeth in these 

 specimens seem to indicate full-grown individuals. It is inter- 

 esting to note that this species was common at a point so far 

 north as this region. 



Species from Rancho La Brea 

 CITELLUS BEECHEYI CAPTUS, n. subsp. 

 Type no. 11264, a portion of the skull without nasals, pre- 

 maxillae and incisors, Cotype no. 12404, a left ramus of the 

 lower jaw with P 4 , M x , M 2 . Both specimens from locality no. 

 1059, Rancho La Brea, Los Angeles County, California. 



