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Show 1012 DR. J. E. GRAY ON THE RHINOCEROTID^E. [Dec. 12, erect and more expanded behind than in front; the front edge of the hinder nasal aperture is narrow, and rather in front of a line even with the hinder edge of the third grinder; the length of the palate from the front edge of the intermaxillaries is rather longer than from the end of the palate to the suture between the basal sphenoid and the basal occipital bone. The vomer is compressed, and forms a well-marked broad ridge, which is much higher in front, and divides the internal nostrils. The lower jaw has the incisors just developed, and slightly projecting beyond the alveolus; they are oblong, with a rather sharp edge on each side. There are cavities for four grinders on each side; the small first ones are lost; the second and third are equally developed, just projecting and with smooth enamel edges; and the fourth are being developed, the crown being sunk rather below the alveolar edge. Rhinoceros cucullatus (Wagner, Schreb. Saugeth. vi. 317; Giebel, Saugeth. 202), described from a specimen in the Munich Museum, appears to be only a specimen of R. unicornis, with a second horn added by the preserver. 3. RHINOCEROS NASALIS. (Figs. 1, 2.) B.M. Skull elongate, the forehead and nose flat above, nose rounded on the sides in front; the nasal bones narrow, tapering, short, about two-fifths of the entire length of the skull from the nasal to the occipital crest; the zygomatic arch flat; lachrymal bone narrow, oblong, erect; the upper jaw only slightly contracted in front of the grinders (3\ inches wide). Hab. Borneo. There are two not quite adult skulls in the British Museum (nos. 7236 and 723c) which appear to belong to this species. Jhey slightly differ from each other; but this may be sexual. They agree with R. unicornis in the flatness of the crown, forehead, and nose, and in the nose being rounded on the sides, and also in the slight contraction of the upper jaw in front of the grinders, and in the comparative flatness of the zygomatic arch. They chiefly differ from the skull of that species of the same age,- 1, in the greater length of the skull; 2, in the breadth and flatness of the forehead; 3, in the line of the forehead not being so concave; 4, in the comparative slenderness and shortness of the nasal bones, they are only two-fifths of the entire length of the skull from the end of the nasal to the occipital crest, while in the skull of R. unicornis, nearly of the same age, in the College of Surgeons (no. 2975) the nasal bones are at least four-ninths of the entire length. The nasal bones are narrower and more tapering, being about once and one-half the length of the breadth of the base. The upper jaw behind the internasa! is only slightly contracted. They are at once known from R. javanicus by the greater length and narrowness of the skull, and the rounded form of the upper part of the nose, but they agree with the non-adult skull of that species in the shortness of the nasal bones. The two specimens rather vary from each other in the width of the nasal. 723 b is a not quite adult animal; it is just showing |
