RODENTIA—LEPORIDAE—LEPUS. 573 
Mes... Linn. 
Lepus, Linnaeus, ‘‘ Syst. Nat. 1735.” 
Molars, $=: 3 ears large, nearly as long or longer than the head ; tail short and bushy ; hind legs powerful, and much 
longer than the fore legs. 
The hares are distinguished by the above characteristics essentially from the Pikas (Lagomys,) 
to which others, derived from the shape of the skuJl,as mentioned under Lagomys, may be 
added. About twenty species are considered by Waterhouse as well established for the Old 
World ; not quite so many in North America. This continent does not appear to possess any 
genuine rabbits like the European ZL. cuniculus, characterized by living gregariously and con- 
structing burrows in which the young are raised, while the hares proper are more or less 
solitary, and merely make nests or forms of grass on the surface in which they sit. The young 
rabbits are born blind and naked, while the hares are said to have the eyes open and the body 
covered with hair at birth. Waterhouse points out some differences in the osteological structure 
of the European rabbit and common hare, but he does not show that these are other than 
specific, or whether the peculiarities of either are shared or not by any other species. As before 
stated, there do not appear to be any true rabbits in North America; nor, indeed, are authors 
clear as to whether the habits and peculiarities of Lepus cuniculus are shared by any other 
species of Old World Lepus. 
I have omitted any generalities respecting the skeleton, skull, and teeth of Lepus, as these 
have been given by Waterhouse in a much more detailed and comprehensive manner than my 
time and ability will allow. In the examination, however, of large series of skulls of the 
American and European hares, I have detected certain characteristics which exhibit quite a 
remarkable relation to the different groups into which they are divisible, as based on the pro- 
portions of the feet and ears. These refer chiefly to the absolute size of the skull, as compared 
with the body ; its proportions and curvature above ; but most particularly to the character of 
the post-orbital process of the frontal bone. Thus, in the varying hares of Kurope and America, 
including Lepus timidus, in addition to L. variabilis, var. borealis, glacialis, americanus, wash- 
ingtonti, and campestris, the skull is very broad, the width being very nearly, if not quite, one- 
half the length. The muzzle anterior to the molars is higher than wide. The upper outline 
is much curved, especially posteriorly. The post-orbital processes of the frontal bone have their 
exterior borders strongly divergent behind, so that they would meet if produced anteriorly 
considerably within the end of the suture of the nasal bones. The divergence of their posterior 
border is still greater, and the process itself does not come in contact with the cranium behind, 
but bounds a wide notch. 
elIn the next section, composed of L. californicus and callotis, the skull is much narrower, the 
width considerably less than half the length. The muzzle anterior to the molars is wider than high- 
The nasal bones are longer ; the upper outline less curved. The exterior borders of the post- 
orbital processes are nearly parallel ; the postero-internal less divergent. The process usually 
extends back so as to come in contact, by its truncated extremity, with the cranium, but there 
is seldom any anchylosis, and quite frequently there is a slight interval. When in contact, the 
