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Show 1870.] ANATOMY OF THE PRONGBUCK. 361 inches. Vertical depth of the anterior nares 1*7 Vertical depth of the posterior nares 1*6 Distance between tips of horn-cores 9*0 Length of horn-core 5*0 Its greatest breadth-that is, where prong is given off-in different skulls from 1*5 to 2*0 Distance between roots of horn-cores 2*5 (c) Inferior maxillary bone.-Dr. Gray's figure of the mandible (Cat. of M a m . B. M . 1852, tab. xv. fig. 1, Dicranoceros furcifer), though small, sufficiently indicates the peculiarities of outline distinguishing this bone. As is therein shown (and in the present fig. 6, B), the direction in which the ramus rises and recedes from the body is more backwardly oblique than in most Ruminants ; and this is rendered the more apparent by the unusual rounding-off of the angle. The coronoid process is long, narrow, and straight, or wanting in that convexity of its upper border met with in most Cervidae and Bovidae. The sigmoid notch is both short and shallow, and the rather flat-topped facet of the small condylar head almost deficient in neck, whilst its transverse and antero-posterior diameters are not great. The ramal angle, as mentioned above, is the reverse of prominent, and possesses in some specimens a widish but shallow emargination towards the body end. The dental portion of the body is only moderately deep behind, and is concave below forwards to the diastema. This is long, laterally compressed, and relatively deep, with a sharp upper border; the terminal incisive expansion is of moderate breadth. The dimensions of the mandible are :- inches. Extreme length from coronoid process to cutting-edge of incisors 10 Length from the angle to the roots of the incisors 8*5 Distance from the front of symphysis to first premolar 3*4 Row of lower grinding-teeth 3*2 Vertical height, a line being dropped from coronoid process . . 5*2 Length of coronoid process 1*5 Depth of the bone at the middle of the last molar 1*4 Breadth of the bone at the angle 1-6 (d) The skull of Rupicapra contrasted with that of Antilocapra.- The Prongbuck has been closely associated with the Chamois by most classificators of the Artiodactyla, chiefly because of the upright and supraorbital position of the horns, and recurvation of their tips. Mr. Turner, who, in his ' Generic Subdivision of the Bovidae,' has dwelt more generally on the characters of the skull, still considers them in some degree allied, and follows Dr. Gray in ranking them and others under the title of caprine Antelopes. The cranium of each, no doubt, has some characters in common ; but in many points the differences are as well pronounced. Among other features, the skull of the Chamois compared with that of the Prongbuck shows the following divergences:-1. The |