1 CLASSIFICATION OF THE HARES AND THEIR ALLIES By MARCUS WARD LYON, Jr. CONTENTS I. Introduction 322 II. List of names that have been applied to the existing Hares, Rab- bits, and Pikas 325 III. List of the existing species of the DupHcidentata, arranged by genera and subgenera 334 IV. General consideration of the skeleton and teeth of the DupH- cidentata 337 V. Table showing principal osteological differences between the fam- ilies Ochotonida: and Leporidje 384 VI. Keys to Families, genera, and subgenera of DupHcidentata Based primarily on dental characters 386 Based primarily on cranial characters 387 Based primarily on skeletal characters other than those of the skull 389 VII. Detailed account of the genera and subgenera of the existing Hares, Rabbits, and Pikas 389 Family Leporidae Genus Lepits 389 Subgenus Lepus 394 Subgenus Poccilolagus 395 Subgenus Macrofolagiis 395 Genus Sylvilagus 396 Subgenus Sylvilagus 401 Subgenus Microlagus 402 Genus Oryctolagus 402 Genus Linuiolagiis 406 Genus Bracliylagus 4" Genus Pronolagus 416 Genus Romerolagus 420 Genus Nesolagiis 425 Genus Caprolagiis 426 Genus Pentalagus 428 Family Ochotonidae 43 Genus Ochotona 43' Subgenus Ochotona 43^ Subgenus Conothoa 43^ Subgenus Pika 43^ VIII. Geographical distribution 439 IX. Bibliography 44° X. Explanation of plates 443 321 : 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. : lvon] the hares and their allies 323 49589' Sylz'Hagits Horidanus Florida. 89514" Sylvilagus floridanus malhirus Four Mile Run, Virginia. 16248^ Sylvilagus floridanus malluvus Carlisle, Pennsylvania. 49624^ Sylvilagus floridanus transitionalis Monroe county, New York. 11644^ Sylvilagus niittaUii Fort Bridger, Wyoming. 92965^ Sylvilagus truei jMetlaltoyuca, Mexico. 113432^ Sylvilagus niinensis Chapada, Brazil. 49665^ Sylvilagus niinensis, young Chapada, Brazil. 74883" Sylvilagus sp Lewiston, Idaho. 94197" Sylvilagus sp Monitor valley, Nevada. 49580^ Limnolagus paludicola Florida. 49645^ Oryctolagus cuniculus Germany. 49648^ Oryctolagus cuniculus England. 49386^ Oryctolagus cuniculus, lop-eared Domestic. 49677^ Oryctolagus cuniculus, Belgian hare. ... United States. 57954" Romerolagus nclsoni Mt. Popocatepetl, Mexico. 22972^ Pronolagus crassicaudatus South Africa. 93695^ Brachylagus idahoensis lone valley, Idaho. 93596" Brachylagus idahoensis lone valley, Idaho. 91188" Ochotona (Pika) sa.ratiUs Cabinet mts., Idaho. 30990" Ochotona (Pika) saxatilis Salmon River mts., Idaho. 49620^ Ochotona (Pika) saxatilis Oregon. 49500^ Ochotona (Ochotona) ladaccnsis Hanle district, Ladak. Besides these, I have had access to a large number of skulls, mostly of American species. These are indicated at the end of the description of each genus or subgenus. The material examined has been altogether too limited for any- thing like complete work on this interesting group of rodents and much more must be compared before a satisfactory determination of various relationships can be made. Yet, in the course of study so many interesting points have been disclosed, some already pub- lished and some apparently never before recorded, that it seems advisable to set forth our present knowledge in as complete a manner as can now be done. As an aid to a clearer understanding of the text, the following outline of the classification therein adopted is here given The existing Duplicidentata are considered as composed of two distinct families, the Leporid?e, hares and rabbits, and the Ocho- tonidse, pikas. The Leporid?e are regarded as containing the following ten dis- tinct genera, most of which have heretofore been recognized as sub- genera. Two are here described as new. ^ United States National Museum. "United States National Aluseum, collection Biological Survey, Department of Agriculture. 3^4 SMITHSONIAN MISCELLANEOUS COLLECTIONS [vOL. 45 1. Lcpus, with the largest number of species and the most ex- tensive geographical distribution. It contains three well-marked subgenera and a number of species which from lack of available material cannot now be satisfactorily classified. (a) Subgenus Lepus, represented by the well-known species, timidus, arctinis, europceus, campcstris, and their allies. {h) Subgenus Macrotolagiis, containing the jackass hares of Mexico and southwestern United States. ( f ) Subgenus Pcecilolagits (new), containing Lcpus amcricamis and the related species. 2. Syk'ihigus, with two subgenera. (a) Sylvilagns proper, containing the wood rabbits or cotton- tails of North and South America. {h) Microlagiis, containing a few small forms from western and southwestern United States. 3. Oryctolagns, represented by the rabbit of the Old World, O. cunicuhis. 4. Liiiuwlagiis, containing the swamp rabbits and water hares of southern United States. 5. Brachylagus, a small short-tailed rabbit of western United States, B. idahoeiisis. 6. Pronolagns (new), containing the cape hare of South Africa. 7. Rouierolagus, the peculiar little rabbit of Mount Popocatepetl, Mexico. 8. Ncsolagus, from Sumatra. 9. Caprolagus, from the southern foothills of the Himalayas. 10. Pcntalagus (new), from the Liu Kiu islands south of Japan. The family Ochotonidae contains but one existing genus, Oclwfona, with a number of species inhabiting the northern parts or high mountain ranges of the Northern Hemisphere. It contains three well-marked subgenera. (a) Ochotona, containing ladaccnsis, and allied forms from central Asia. {h) Pika, containing alpina and the North American species. (c) Conothoa (new), represented by roylii and related species. In the preparation of this paper I have received from Mr. Gerrit S. Miller, Jr., many valuable suggestions and generous criticisms, which are here gratefully acknowledged. My thanks are due also to Dr. C. Hart Merriam for the use of all the skeletons and many separate skulls of the Duplicidentata in the collection of the Biolog- ical Survey of the United States Department of Agriculture ; to Dr. Milton J. Greenman for the use of two specimens of Pentalagus lvon] the hares and their allies 325 fiinicssi in the W'istar Institute of Anatomy, Philadelphia, and to Dr. J. A. Allen for the use of a skeleton of Lcpiis gicliigaiiiis and skull of Ochotona kolyiiiciisis in the American Museum of Natural History, New York. I have also to thank Mr. Oldfield Thomas, who presented to the U. S. National Museum a skeleton of Orycfo- iagiis cuniciilns and two young skeletons of Sylvilai^us miiicnsis; Dr. E. A. Mearns, who collected for the National Museum a series of skeletons of Sylz'ilagits HoridiDiiis and the only availahle skeleton of Liniiiolagiis; and Messrs. Witmer Stone and James A. G. Rehn for furnishing references and copies of Blyth's figures of Coprolagiis. II. LIST OF NAMES APPLIED GENERICALLY OR SUBGENER- ICALLY TO THE EXISTING HARES, RABBITS, AND PIKAS ABRA Proposed by Gray (Cat. Mammals, Birds, etc., presented by B. H. Hodg- son to Brit. Mus., 2d ed., p. 11, 1863) as a subgenus of Lagoinys. Type Lagoiitys (Alva) curziniicc Hodgson from the Himalayas of Sikkim, India. Preoccupied by Abra Le.\ch, 1818, a genus of Mollusca, fide Palmer, North American Fauna, No. 23, pp. 71, 860, January 22,, 1904. BRACHYLAGUS Proposed by ^Miller ( Proc. Biol. Soc. Washington, xni, p. 157, June 13, 1900) as a subgenus of Lcpus for L. idahocnsis Merriam, the only species and the type. In the present paper it is considered a distinct genus. CAPROLAGUS Proposed by BIytli (Journ. Asiatic Soc.