58 THE AMERICAN NATURALIST [Vol. XLIV 



sense to designate the two long-known European species; later 

 their use became greatly broadened and their application more 

 or less interchangeable, with different restrictions by different 

 authorities and in different countries. Mr. Nelson would con- 

 fine the use of the term hare, so far as American species are con- 

 cerned, to the restricted genus Lepus ( including the varying 

 and Arctic hares and the jack rabbits), and employ the term 

 rabbit for the " cotton-tails" or smaller brush rabbits and 

 swamp rabbits (genus Sylvilagus and allied forms). The hares 

 are, generally speaking, larger than the rabbits, live mostly in 

 "forms," and bring forth young with open eyes and well- 

 clothed with hair; many of the rabbits are known to bring forth 

 their young naked and blind; while some of them burrow, others 

 live in forms, like the true hares. 



Formerly all the species of Leporida? were referred to the 

 single genus Lepus, but later, mainly within the last decade, 

 several genera have been recognized by the leading authorities 

 on the group, together with a number of subgenera. Mr. Nelson 

 arranges the North American species in four genera — Lepus, 

 Sylvilagus, Brachylagus and Komerolagus. The last two are 

 monotypic with very restricted ranges; the rest of the species 

 are assigned to Lepus (with two subgenera, Lepus = Arctic and 

 varying hares, and Macrotolagus "jack rabbits") and Sylvi- 

 lagus (also with two subgenera, Sylvilagus = "cotton-tails" or 

 brush rabbits) and Tapeti (swamp rabbits. The latter includes 

 most of the species of Central and South America). 



The hares of the subgenus Lepus (the Arctic and varying 

 hares) have a double molt, being brown in summer and white in 

 winter, while the other species are believed to molt, for the most 

 part at least, only once (in fall), and the only seasonal change 

 of color is due to the fading and abrasion of the long-worn coat. 

 Formerly it was supposed that the white winter coat of all the 

 northern hares was due to a change of color in the hair itself of 

 the summer coat. On this point Mr. Nelson says : 



This supposed change of color in the hairs, he further says, 



'Bull. Am. Mus. Nat. Hist., VI, pp. 107-128, May 7, 1894. 



