No. 2391. DESCRIPTIONS OF PLEISTOCENE VERTEBRATA—HAY. 629 



Named in honor of Dr. Marcus Benjamin, editor of the Proceedings 

 of the the United States National Museum. 



Besides the fragment of the lower jaw which is made the type of 

 this species there is a considerable number of other parts referred to 

 it provisionally. The principal of these are the following: A right 

 upper incisor (Cat. No. 10184); the greater part of both maxillae 

 (Cat. No. 10185), containing the left first true molar and the sockets 

 of the other teeth, excepting the front premolar; an interparietal 

 bone (Cat. No. 10186); one lumbar vertebra (Cat. No. 10187); a 

 complete humerus (Cat. No. 10198); five fragments of innominate 

 bones (Cat. Nos. 10189, 10190); three complete femora (Cat Nos. 

 10191, 10192); the upper half of a right tibia (Cat. No. 10193); a tibia 

 lacking the upper epiphysis and a part of the distal end (Cat. No. 

 10194); and a distal end of another tibia (Cat. No. 10195). These 

 bones are described below: 



The type ramus is figured (pi. 121, fig. 1) as seen from the inner side. 

 The height at the first molar is 16 mm. The anterior premolar is 

 only slightly larger than the other teeth. In it, as in the other 

 teeth, the enamel is thin and delicate, thickest where it forms the 

 front wall of the main outer valley. In the anterior tooth this front 

 wall is angulated and slightly wavy in its course. The rear part of 

 the loop is very thin and distinctly crenulated. In the front border 

 of this tooth there is a narrow but pretty deep inflection of the 

 enamel. In the outer face of the front half of the tooth there is a 

 wider inflection of the enamel, and this also is crenulated. In the 

 other teeth the anterior part of the loop of enamel is thickened and 

 forms a ridge across the grinding surface. The hinder part of the 

 loop is crenulated. The writer was on the point of referring the 

 fossil to Lepus campeslris, but an examination of many specimens of 

 its various subspecies resulted in finding that in none of them did the 

 hinder element of the loop show more than feeble traces of crenula- 

 tions. Other species, as L. alleni and L. gaillardi, . present these 

 constantly. These species, however, differ in other ways from the 

 fossil species. 



Figure 2 of plate 121 presents a view of two maxillae of one indi- 

 vidual which is believed to belong to the species described. The right 

 first molar is present. The parts resemble the corresponding ones of 

 L. campestris. A complete upper right incisor appears not to differ 

 from that of the species just named. The groove is nearer the inner 

 border of the tooth, and it retains its cement. L. californicus rarely 

 has cement in the grooves of the incisors. 



The lumbar vertebra present resembles more that of a species of 

 Sylvilagus than of Lepus. Perhaps it does not belong to the species 

 being described. The humerus (pi. 121, fig. 5a) is 91 mm. long. It is 

 somewhat more compressed than one 95 mm. long and supposed to 



