630 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.59. 



belong to Lepus callotis. At the middle of the length the fore-and-aft 

 diameter is 6.6 mm.; the side-to-side diameter, 4.1 mm. In the 

 recent humerus mentioned the diameters are 6.1 mm. and 5 mm., 

 respectively. 



The parts of the innominate bones present (pi. 121, fig. 56) resemble 

 those of the supposed L. callotis, but are slightly smaller. 



The largest femur present is 115 mm. long, quite exactly the length 

 of that of L. " callotis. ." It is broader across the inner and outer 

 processes at the upper end than in L. " callotis, 11 and narrower across 

 the condyles. The femur figured (pi. 121, fig. 3) is 100 mm. long. 

 The imperfect tibiae present are somewhat slenderer than those of 

 the recent skeleton used for comparison. One is figured (pi. 121 , fig. 4.) 



Genus BRACHYLAGUS Miller. 



Numerous bones of many parts of the skeleton of a species of 

 Brachylagus are present. Usually they are more or less injured, but 

 taken together they furnish the characters of a species apparently 

 new. The remains appear to require some modification of the charac- 

 ters that have been imputed to the genus. None of the specimens 

 retain the first upper premolar. According to Lyon 18 in the next 

 four upper molariform teeth the infolding of the enamel extends about 

 halfway from the inner to the outer face of the tooth, and this enamel 

 is not crenulated. However, it is seen to be occasionally slightly 

 crenulated. In the fossil species at hand the enamel is very dis- 

 tinctly crenulated, and the infold appears to extend outward slightly 

 farther than it does in B. idahoensis. The first lower premolar con- 

 forms to the description of that of the type species of the genus. The 

 hinder portions of the other lower molariform teeth are smaller than 

 the anterior portion; that is, the teeth differ from those of B. idahoensis 

 principally in the crenulated character of the infolded enamel of the 

 upper teeth. 



BRACHYLAGUS BUOWNI, new species. 



Plate 121, figs. 6-18. 



Type specimen. — A palate containing three grinding teeth on the 

 right side and four on the left (Cat. No. 10196 U. S. N. M.). 



Type locality. — Coconino plateau, Arizona. 



Type formation. — Early Pleistocene. 



Diagnosis. — Size larger than that of B. idahoensis. Upper molar- 

 iform teeth with the enamel of the inner reentrant fold distinctly 

 crenulated. 



This species, as represented by the skull, was larger than B. ida- 

 hoensis, but the rest of the skeleton indicates an animal of nearly 

 the same size. Perhaps the skull was that of an unusually large 



» Smiths. Misc. Coll., Quart. Issue, vol. 50, p. 412. 



