Proceedings of the Scientific Meetings of the Zoological Society of London 1870

Page 437

1870.] ANATOMY OF THE PRONGBUCK. 357 pering forwards almost to a point, which reaches the hinder border of the ascending or nasal portion of the maxilla. The surface of the bone is smooth and not impressed for the reception of a crumen ; and its superior border is excluded from touching the nasal by the intervention of a large open space or fissure (/). The lachrymal of the alpine Gems answers to the above, but the fissure is reduced to a minimum. Most Deer have the bone broadly triangular and deeply sunk for the reception of tbe sub­orbital gland. The facial plate of the os unguis in the Camelopard is relatively small. In the Antelopes the lachrymal varies accord­ing to the presence or absence of infraorbital fossa and fissure ; but in most instances its breadth anteriorly is relatively greater than in the Prongbuck. The interspace between the frontal, nasal, lachrymal, and maxil­lary bones, denominated the suborbital fissure (/, fig. 6, A), is in the Prongbuck, as in most Deer and in the Giraffe, a proportionally extensive area-differing thus from the Bovidae, where it is notable rather by its diminutive size or absence than conspicuous by its dimensions. The space in question is a shallow depression floored by a thin, smooth, delicate osseous plate, which overlies the post-turbinal bone, and partly of the frontal sinuses. It has an elongate sinuous or/"-shape, 1*8 inch in antero-posterior diameter, and 0*4 inch in breadth at the widest point. Its anterior horn terminates obtusely or in a rounded manner; the posterior one narrows more, and diverges considerably from its fellow of the opposite side. The fronto-lachrymal suture passes outwards half an inch behind the posterior angle of the fissure. Those Antelopes with a suborbital fissure have it elliptical and very diminished as regards length and breadth from the foregoing ; a few examples (Damalispygarga, Gray, for one) have it placed far forwards. It is large in all Deer, and broadly triangular; but ex­ceptionally it is found partially lyriform, as obtains in the Chinese long-tailed species, Elaphurus davidianus, Alph. Milne-Edwards. In the Giraffe it is a large crenated-edged oval. The frontal, or fore part of the vault of the skull, is broad and remarkably flat, rising, however, a very little towards the coronal suture. The width between the horn-cores is from 2| to 3 inches. At their inner base, well forwards, is a very large elliptical supra­orbital foramen (s o f fig. 6, A), which enters quite through the roof of the orbit; a superficial shallow groove for a venous sinus passes betwixt the foramen and the lyrate supraorbital fissure. The compressed dagger-shaped horn-cores (c, fig. 7, B), flattened from without inwards, thickest behind, and narrow-edged in front, spring well nigh directly over the orbit, and with divergently inclined postures, overtop the eye, the tips being 9 inches apart. They are each 5 inches long, and at their broadest part, or where the prong-is given off, measure, in different crania, from 1*5 to 2 inches in diameter. From the lateral position whence the osseous horn-sup­ports start, the orbito-frontal rings are partly deprived of that salient configuration which essentially belongs to them.