282 MONOGRAPHS OF NORTB AMERICAN RODENTIA. 



external and osteological characters, though presenting many features of 

 general resemblance. No subdivisions of the family can apparently be made. 

 having a higher than generic value, the species being, in fact, apparently all 

 strictly congeneric. 



The most obvious external distinguishing characters of the Hares arc 

 their lengthened hind limbs, their large, sometimes very large, ears, and 

 short, sometimes rudimentary, bushy, erect tail; most of the species have a 

 thick coat of very soft loose fur. The skull presents also distinguishing 

 features, namely, the large, deep, flattened rami of the lower jaw; the per- 

 forated or reticulated condition of the facial surface of the maxilla; the large 

 size of the orbits, in which the foramina arc confluent; the large size of the 

 anterior palatine foramina, and the reduction of the palate to a mere bridge 

 between the premolars; the large size, in short, of all the openings of the 

 skull; the possession of more than the usual number of teeth, including both 

 molars and incisors. The dental formula is as follows : — 



T 2-2 p 0-0 p 3-3 M 3-3 1G _ 9q 

 L T=1' C -U^)' R 2=2' M -3=3 = 12- 28 - 



The molars are rootless. Lagomys shares with Lcjms the possession 

 of several of these cranial characters, but they are much less developed. 



In respect to the general skeleton, besides the elongated, hind legs and 

 feet, the Hares have the acromion-process of the scapula provided with a 

 spine (metacromion) directed posteriorly at right angles to the axis of the 

 scapula. The vertebral processes are generally long and slender, the thoracic 

 vertebrae being provided with "remarkably long, single, compressed, median 

 hypapophyses", not usually present in the other Rodentia. 



Genus LEFTS Linn. 



Lcpus Linn., Syst. Nat. 



Uydrolagus Gray, Ami. & Mag. Nat. Hist., 3d ser., xs, 221, 18C7. 

 Sylvilagus Gray, ibid., 221. 

 Eulagos Gray, ibid., 222. 

 Lepus Gray, ibid., 222. 

 Tap, i, Gray, ibid., 224. 

 Cunivulua Gray (nee Wagler), ilnd., 225. 



Oryctolagus Lilueborg, Fauna ofver Sverigcs och Norses, 417, 1873. Typo L. eunieuluB Linn.; benco 

 = Cuniculus Gray. 



The characters of the genus have been sufficiently indicated in the 

 preceding description of the family. 



