THE HARES AND TTIKIR ALLIES 



389 



C. Key to the Families and Genera of Hares, Raiiuits, and Pikas, Rased 

 ON Skeletal Characters Other than Cranial 

 (Because of insufficient material, the genera Caprula^ius, /'I'lilaUif^us, and 

 Ncsolagiis can not be incorporated in this key.) 



a') Transverse process of 7th cervical vertebra, with no vcrU'bral foramen, 

 thoracic vertebras 17, lumbar vertebrae 5, sacrum much longer than wide. 

 Acromion about 3 times the length of actual scapular spine, foot sliort, 

 basal width of metatarsals contained i^ times into length of longest 

 metatarsal. Family Ochotonid.e. Genus Ochotona, p. 431. 

 a) Transverse process of 7th cervical vertebra, with no vertebral foramen, 

 thoracic vertebnc 12, lumbar 5, sacrum as wide as long. Acromion 

 process about half the length of the actual scapular spine, foot long, 

 basal width of nu'tatarsals contained at least 2 times and usually 2^/^ 

 times into the length of longest metatarsal. Family Leporid^':. 

 b) Cervical vetrcbne lengthened individually, ulna much reduced in size, 

 smaller than radius and behind that bone, ventral half of anterior 

 ribs much broadened. Genus Lcpus, p. 394. 

 b') Cervical vertebrae individually shortened, ulna and radius subequal 

 in size, the ulna toward the outer side of radius. Ventral half of 

 anterior ribs not broadened. 

 c) Transverse processes of the lumbar vertebra; not conspicuously 

 ridged, and the angle between the process and the side of the 

 centrum not conspicuously filled in with thin bone. 

 (/) Tubercles of anterior ribs not well marked. (Jenus J'rono- 



lagus, p. 416. 

 d') Tubercles of anterior riijs usually well marked. 



c) Presternum with well marked keel, xiphisternum 

 large and stout, etiually enlarged at both ends, longer 

 than presternum. Genus Oryctolagus, p. 402. 

 e') Presternum with keel not well marked, xiphisternum 

 shorter than presternum. Genus Sylvilagus, p. 396. 

 c') Transverse processes of lumbar vertebrae conspicuously ridged or 

 else angle between the process and the side of centrum con- 

 spicuously filled in with thin bone. 

 f) Anterior portion of presternum conspicuously enlarged, like 



presternum of Ochotona. Genus Romcrolagus, p. 420. 

 f) Anterior portion of presternum not conspicuously enlarged. 

 g) Size small, each transverse process of the lumbar verte- 

 bra; with a well marked longitudinal ridge. Genus 

 Brachylagus, p. 411. 

 g') Size larger, angle between transverse process and side of 

 centrum of lumbar vertebra' filled in with thin bone. 

 Genus Limnolagiis, p. 406. 



VII. DETAILED ACCOUNT OF THE GENERA AND SUR- 



GENERA OF THE EXISTING HARES, RAP.P.ITS, 



AND PIKAS 



Family LEPORID/E 

 Genus LEPUS Linnasus 



1758. Lcpus Linnaeus, Syst. Nat., loth ed., i, p. 57. 

 1829. Cliionobatcs Kaup, Entw. Gesch. und Natur. Syst. Europ. Thier- 

 welt, I, p. 170. 



