Under the term CEgosceridm (GTgosceros, Pallas) we have brought together the closely allied genera Capra and Ovis. The Goats are characterised chiefly by their long horns, which are directed upward and backward, are more or less angular in front, rounded behind, and generally marked by transverse bars or ridges. The chin is clothed with a long beard. The Sheep which have no beard differ mainly in having the horns directed at first backward, and subsequently bent spirally forward. Between the toes at the anterior aspect of the feet is situated a special glan dular sebaceous sac ; this structure is also found in other ruminants, — the Rein-deer, for instance. Neither the Sheep nor Goats exhibit the lachrymal sinuses so character istic of the majority of the Antelopes and Stags.
The Bovidce present few anatomical pecu liarities not shared by the preceding genera. As regards external configuration, however, they are at once recognised by their bulky massive size, the broad muzzle, and powerful limbs (fig. 325.). The horns are directed laterally, with an inclination upward more or less curved. In their habits and in the struc ture of the skin, some of the species, the Buffaloes, for example, approach the pachy dermatous type.
Ostedogy. — The general form of the skull in ruminants, when viewed laterally, is that of an isosceles triangle, the base of which is represented by the occipital crest and rami of the jaw, and the apex by the incisive pro minence ; but exceptions occur, as for instance, in the common sheep, where the frontal bones are so much arched as to produce a somewhat oval figure, and in the camel, where, owing to the abrupt termination of the nasal and sudden depression of the intermaxillary bones, an obliquely, quadrilateral form is the result (fig. 331). The forehead is usually straight and elevated, the orbits are placed wide apart, and the muzzle, except in Bovidte, is attenuated and compressed. Throughout the whole order there prevails considerable disparity as respects the cranium and face ; the bones of the latter occupy fully two thirds of the entire length of the skull, and the area of the face on section is nearly double that of the cranium.
Bones of the cranium.— Eight bones enter into the composition of the adult cranium; viz , an occipital, a parietal, two frontal, a sphenoidal, an ethmoidal, and two temporal; and, in addition to these, some species are provided with two ossa triquetra or inter parietals.
The occipital bone (11,.fig. 326.), as in most of the mammalia, is originally divided into four, one superior, one inferior, and two lateral pieces (11',.fig 326.). These become early consolidated, and in the calf at the time of birth they are firmly united together and to the parietal and interparietal bones lying immediately in front. The occipital crest is prominent in the Llamas, and still more fully developed in the true Camels. In Bovidm the crest corresponding to the occipital is formed by the junction of the parietal and frontal bones, the superior occipital remaining flat. In ruminants generally, the paramastoid pro cesses (1 fig. 326.) are much elongated, falci form, and curved inwards, and between these and the occipital condyles (i) a very deep fossa intervenes. In Carnelid, at the angle formed by the union of the petrous portion of the temporal with the lateral and superior occipitals there is a large opening on either side. In this family the anterior condyloid foramina are of moderate capacity, but in Cervidm they are of great size and some times four in number, in which case two remain small. In CEgosceridm and Bovidm they are also large and occasionally double.
The parietal (9*) is single, and with a few trifling variations, is articulated to the cranial bones in the usual manner. The lambdoidal or parieto-occipital suture lies considerably in front of the crest, except in Bovidm, where it lies below, and is separated from the frontal suture by the intercalated and narrow wedge-shaped parietal bone. The CEgosceridm have the parietal in the form of a flattened band, encircling the cranium and extending between the orbitar wings of the sphenoid on either side (b, fig. 335.). It is broader in the goats than in the sheep. In Bovidae the parietal does not extend so far forward (b. fig. 327.). In the Giraffe the lateral processes of the parietal are narrowed to a mere point, but the body of the bone which reaches from between the horns as far back as the occipital crest has a longjtudinal diameter of fully six inches. The coronal or fronto-parietal suture in this Epecies and a few other genera is situated in a line with the osseous protuberances which support the horns. It is most frequently placed behind ; in the Gazelles, however, it appears in front.