32 2 SMITHSONIAN MISCELLANEOUS COLLECTIONS [vOL. 45 



I. INTRODUCTION 



The object of this paper is to give an account of the principal 

 osteological features of the hares, rabbits, and pikas or duphcidentate 

 rodents, the DnpHcidentata, and to determine their family, generic, 

 and subgeneric relationships. 



The subject is treated in two ways. First, there is a discussion of 

 each part of the skeleton and of the variations that are found in 

 that part throughout the various groups of the existing Dupliciden- 

 tata. Second, each of these groups is separately considered, and 

 the characters of its skeleton described. The treatment of the 

 osteology in these two ways is followed by three keys to the genera 

 and subgenera, one based on cranial characters, one on dental char- 

 acters, and one on skeletal characters aside from those of the skull. 



Before taking up the osteological discussion, however, I give the 

 histories of the various generic and subgeneric names that have 

 been applied to the existing hares, rabbits, and pikas. 



As the geographical distribution of the various groups shows 

 some interesting correlations with zoogeographic areas, a few re- 

 marks are made on that subject. 



I have had at my disposal the following skeletons : 



1048^ Lepiis (Lepus) tiiiiidus Sweden. 



1049^ Lepus (Lepus) timid us Sweden. 



49622^ Lepus (Lepus) caiiipesfris Nebraska. 



49623' Lepus (Lepus) campestris Kansas. 



2276' Lepus (Lepus) bangsii Newfoundland. 



2277' Lepus (Lepus) bangsii Newfoundland. 



18303" Lepus (Lepus) gicliiganus Northeast Siberia. 



836' Lepus (Pcccilolagus) americainis^ Fort Pierre, British America. 



969' Lepus (Pcccilolagus) ainericauus vir- 



ginianus* New York. 



7577' Lepus (Pcccilolagus) americanus rfa///''- Alaska. 



21805' Lepus (Maerotolagus) callotis Locality unknown. 



94198^ Lepus (Maerotolagus) te.viauus Newark valley, Nevada. 



49621' Lepus sp India ; Jumna river. 



49586' Sylvilagus ftoridanus Florida. 



49587^ Sylvilagus floridaiius Florida. 



49588' Syhilagus floridanus Florida. 



' United States National Museum. 

 ^ American Museum of Natural History. 

 *Very young, of little use. 

 * Skeleton incomplete. 



^ United States National Museum, collection Biological Survey, Department 

 of Agriculture. 

 ^ Incomplete. 



