HORNS are appendages to the frontal bones of many of the extensive family of ruminants, and are obviously intended as weapons of defense. In the genus anus (deer) the horns (known also as antlers) are solid, uncovered by epidermis, bone-like in composition, and deciduous. In the genus camelopardaUs (the giraffes) we have the single example of solid persistent horns completely invested whh a hairy integument. In the other hunt-bearing ruminants—as the ox, sheep, goat, and antelope—the horns are hollow, uncovered by epidermis, are composed of a special tissue (Horny Tissues, q.v.) quite different from.bone, and are persistent. In all these cases the horns are attached to the cranial Venda; anti till the hollow horns, excepting' those of the ante lope, the osseous axis is hollowed out into cells communicating with the frontal sinuses and thus admitting the atmospheric air into the interior. The horn of the rhinoceros is quite distinct in character from the horns in any of the ruminants. It is a tezumentary, not an osseous appendage, and is usually described as if it were a mass of hairs which had coalesced. It consists, however, in reality of an aggregation of tubes, round which which the horny matter is arrand in concentric laminm, as in the horny excrescences on the inner surface of the leg of the horse. The first and the third variety—viz., the antlers of the cervida and the hollow horns of the ox, etc.—alone require special notice.
The deciduous horns of the cervidoe at different ages, and their process of growth, are explained in the article DEER. To that description it need only be added that
these horns arc formed on two well-marked morphological types—one group possessing rounded antlers, such as occur in the roebuck and the red-aeer, and the other having the antlers more or less flattened, as in the elk and fallow•deer. A remarkable sym pathy exists between the generative organs and the horns; and the development of the latter may be arrested and their periodical shedding may he prevented by castration. As a general rule, it is only in the male eervidce that horns are developed. In the rein deer, however, they pre common both to the male and female.
In the hollow-horned ruminants, the bony protuberances or "cores" arising from the frontal bones, and supporting the horns, instead of branching like antlers, form more or less solid cylindrical shafts, the surface being protected by ordinary periosteuni (q.v.), and by an extension of true skin, which becomes developed into a dense horny sheath.
Time horns of ruminants are almost invariably two in number, but exceptions occur in the case of the extinct briunatherium and sivatherium, and amongst living species, in the four-horned goat, the many-horned sheep, etc. In the prong-horu antelope there seems to be an approach to the cervine type, there being a prong of some length about half-way up the horn, which may be regarded as analogous to the brow-antler.