80 BULLETIN OF THE 



pruximal end obviously diseased, so that it does not merit description ; the only 

 fact of importance which it shows is the comparative slenderness of the bone. 



So far as the material will enaT)le us to judge, the feet of C'osoryx differ in no 

 important respect from those of lllastomeryx, and the same statement applies to 

 the long bones of the limbs. 



Eestoration of Cosoryx furcatus. 

 (See riate I.) 



This drawing is made from the specimen already described, completed by 

 fragments of others, wliile the feet are drawn from Elastomer ijx; the cervical 

 vertebraj are re[iresented only by the axis, the others being conjectural, as are 

 also the anterior dorsals. The skull is taken chiefly fiom that of the closely 

 allied Eurojiean genus, Fa'ce^menjx, and from specimens of the large Cosoryx 

 ttrca, Cope, belonging to the Smithsonian Institution. The fortunate associa- 

 tion of the mandible in the same specimen with the vertebi'jE, pelvis, scapula, 

 etc., gives a very u.seful standard as to the length and character of the skull, 

 position of the molars, etc. It may be assumed with some confidence that the 

 drawing gives a fairlj' accurate representation of the animal. Marsh's account 

 of the feet uf Cosoryx shows that they were constructed much like those of Blas- 

 tomeryx. In general appearance Cosoryx seems to have had the same light, 

 gracel'ul build as Antilocajira, but with a very dift'erent skull and deer-like 

 antlers. The proportions of the limbs also differ somewhat, the hinder cannon- 

 bone being considerably longer than the fore, while in the prong-buck they are 

 of nearly the same length. Cosoryx was a much smaller animal, the bones are 

 all more slender than in Aiitilocapra, and the carpal and tarsal boues are much 

 higher and narrower proportionately. 



The view held by Cope that Cosoryx is the ancestor of Antilocapra is very 

 probalily the true one. So far as the dentition, the vertebrae, and the lindjs are 

 concerned, the differences between the two genera are only such as might be 

 expected to occur between a Miocene and a recent ruminant. A distinction of 

 some importance, however, consists in the character of the horns. In Cosoryx 

 they are branched, but probablj* not deciduous antlers; in Antilocapra, a core 

 with a horny sheath, which, however, differs strikingly from the horn of the 

 tyi)ical Cavicornia. But the unique branched horn of Antilocapra not improb- 

 ably indicates, as has been suggested by Cope, a remnant of a former l)ranc.hing 

 of the bony core itself, and so this difference does not preclude a genetic con- 

 nection between the two forms. In Cosoryx the antler was almost certainly 

 covered with skin ; its smooth surfiice, as Schlosser points out, shows that it 

 could not have been naked, as in the true deer. 



Both Blastomcryx and Cosorijx are probably to be derived from the species re- 

 ferred to the former genus which occur in the John Day beds, but there is no 

 form yet known in the White River which could have given rise to these John 

 Day ruminants. The latter are most probably descemled from some Palceo- 

 racryx of the Old "World, which migrated to this continent. The very close con- 



