3^8 SMITHSONIAN MISCELLANEOUS COLLECTIONS [vOL. 45 



On the other hand, by a slight extension of the rule recommended in Science, 

 n. s., XVI, pp. 114, 115, July 18, 1902, timidus may be fixed as the type of the 

 genus Lepus, and no radical changes in the generic names of the Leporidfe 

 would result, as would occur by a strict application of the principle of elimi- 

 nation. 



This rule is as follows : 



" A generic name which is the same as that of an explicitly included species 

 (or a cited post-Linngean .synonym of such species) takes that species as its 

 type regardless of subsequent elimination." 



Since Linnaeus could cite no post-Linnasan synonym, the rule can rationally 

 be extended to include, in the case of Linnaeus, the names used by earlier 

 writers. Under timidus, Linnaeus cites Lepus Gesner. 



In the present paper, timidus is regarded as the type of the genus Lepus, 

 and the word Lepus is retained for the species to which it has been commonly 

 applied. 



Pallas (Glires, 1778, pp. 1-70), Gmelin (Linnaeus, Syst. Nat., i, 1788, pp. 

 164-166), Schreber (Saugthiere, vii, pp. 906-918, 1792), use Lepus as the 

 generic name of the pikas as well as of the hares and rabbits. 



The pikas were placed in separate genera, Ochotona Link, 1795 (Beytriige 

 Naturgesch., i, pt. ii, p. 74, 1795) and later Lagomys G. Cuvier, 1798 (Legons 

 d'Anat. Comp. Table, 1800; characterized in Tab. filementaire de I'Hist. Nat. 

 des Animaux, p. 132, 1798). 



From the time of Link and Cuvier until Gray in 1867, the generic name 

 Lepus was used for both hares and rabbits and as the equivalent of the family 

 Leporidas. Gray, however, divided the genus into the following genera : 

 Hydrolagus, Sylvilagus, Eulagos, Lepus, Tapeti, and Cuniculus. At the same 

 time he revived Blyth's genus Caprolagus (under the misprint Carpolagus) 

 which had been proposed in 1845 and subsequently withdrawn by Blyth. 



Gray included in the genus Lepus the following species : 



European. — timidus Linn^us, hybridus Desmarest, aqidlonius Blasius, 

 variabilis Pallas, canescens Nilsson. 



African. — cegyptius Geofkroy, hebessinicus Hemprich and Ehrenberg, 

 isabellintis Ruppell, capensis Linn^us, saxatilis F. Cuvier, crassicaudatus 

 I. Geoffroy. 



Asiatic. — arabicus Hemprich and Ehrenberg, syriacus Hemprich and 

 Ehrenberg, sinaiticus Hemprich and Ehrenberg, nigricoUis F. Cuvier, rufi- 

 caudatus L Geoffroy, tolai Pallas, tibetanus Waterhouse, pallipes Hodg- 

 son, brachyurus Temminck, sinensis Gray, altaicus Brandt. 



American. — arcticus Leach, americanus Erxleben, zvashingtonii Baird, 

 campestris Bachman, callotis Wagner, californicus Gray, longicaudatus Gray, 

 audubonii Baird, trowbridgii Baird. 



Of these crassicaudatus is regarded in this paper as the type of the genus 

 Pronolagus and audubonii and trowbridgii as members of the genus Sylvilagus. 



From 1867 to 1896 not much attention was paid to Gray's division of 

 Lepus, but in 1896 Mearns revived Sylvilagus and Hydrolagus as subgenera 

 of Lepus. 



In the same year, 1896, Merriam described Romerolagus as a new genus of 

 the Leporidse, regarding all the other members of the family as congeneric. 

 From that time on the idea has rapidly spread that the family Leporidae no 

 longer could be regarded as composed of but a single genus. In 1899 Major 



