The two styles of antler which we recognize in the North American deer are too well known to require description. That characterizing the mule deer (_Mazama hemionus_) and the Columbia black-tailed deer (_M. columbiana_), seems never to have occurred in the east, nor south much beyond the Mexican border, and these deer have varied little except in size, although three subspecies have lately been set off from the mule deer in the extreme southwest. The section represented by _M. virginiana,_ with antlers curving forward and tines projecting from its hinder border, takes practically the whole of America in its range, and under the law of variation which has been stated, has proved a veritable gold mine to the makers of names. At present it is utterly useless to attempt to determine which of the forms described will stand the scrutiny of the future, and no more will be attempted here than to state the present gross contents of cervine literature. The sub-genus _Dorcelaphus_ contains all the forms of the United States; of these, the deer belonging east of the Missouri River, those from the great plains to the Pacific, those along the Rio Grande in Texas and Mexico, those of Florida, and those again of Sonora, are each rated as sub-species of _virginiana_; to which we must add six more, ranging from Mexico to Bolivia. One full species, _M. truei,_ has been described from Central America, and another rather anomalous creature (_M. crookii_), resembling both white-tail and mule deer, from New Mexico. The other sub-genera are _Blastoceros,_ with branched antlers and no metatarsal gland; _Xenelaphus,_ smaller in size, with small, simply forked antlers and no metatarsal gland; _Mazama_, containing the so-called brockets, very small, with minute spike antlers, lacking the metatarsal and sometimes the tarsal gland as well. The last three sub-genera are South American and do not enter the United States. Another genus, _Pudua_, from Chili, is much like the brockets, but has exceedingly short cannon bones, and some of the tarsal bones are united in a manner unlike other deer. In all, thirty specific and sub-specific names are now carried on the roll of _Mazama_ and its allies.