lvon] the hares and their allies 401 



The greatest length of the foot about equals the length of the 

 tibia, but in one skeleton. No. 94,197, from Nevada, the foot is longer 

 than the tibia, in this respect resembling the foot and tibia of 

 Brachylagiis. 



The basal width of the metatarsus is contained two and a half 

 times into the length of the third metatarsal, as is commonly the case 

 among other LeporicUe. 



The combined length of the phalanges of the two lateral digits, as 

 well as of the two middle ones, is usually approximately equal to the 

 length of the metatarsals to which they belong. 



The genus Sylviloi^us stands second to Lcpus in point of number 

 of species and extent of geographic distribution. It is a fairly homo- 

 geneous group. A few forms have been classed as a separate sub- 

 genus, an arrangement which is here retained. The teeth on the 

 whole are formed as they are in typical Lcpus. Certain of the 

 Mexican species, however, have the first lower premolar as it is in 

 Liinnolagiis. 



In the form of the cervical vertebrae and the shape of the transverse 

 processes of the lumbar vertebrae, the relative size of the radius and 

 ulna, and in the shape of the pelvis and the ribs, sternum, and scapula, 

 Syh'Uagus seems to be generally similar to Oryctolagiis. The teeth 

 in these two genera are essentially alike. 



There are two subgenera of Syhilagus — Syk'ilagiis proper and 

 Microlagus. No skeletons of the latter are available for examination. 



Subgenus SYLVILAGUS Gray 



1867. Sylz'ilagus Gray, Ann. Mag. Nat. Hist., xx, 3d ser.. p. 221. 



1896. Sylz'ilagus Mearns, Proc. U. S. Nat. :\Ius.. xvin, p. 551. June 



24, 1896. 

 1899. Syhilagus Major, Trans. Linn. Soc. London, 2d sen, vn, p. 514, 

 November, 1899. 

 Type. — Syhilagus Horidaiius nuillunis (Thomas). 

 Geographical Distribution. — Same as for the genus. 

 Diagnosis and Description. — Size larger, skull (pis. lxxvi, 7, 8; 

 Lxxvii, 2; Lxxxvi ; Lxxxvii, i-io) heavier, rostrum often heavier 

 and not so pointed. Postorbital processes long and narrow, attached 

 to skull by a very broad pedicle. The anterior part of the process 

 short, attached to the side of the skull for nearly its whole length. 

 Posterior part of the process long and narrow, the posterior edge 

 touching the cranium, the process thus enclosing a very narrow 

 clavate slit, much narrower than the width of the postorbital, which 

 helps to form it. 



Spjcies in this subgenus, see p. 336. 



