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Show 462 DR. J. MURIE ON SAIGA TARTARICA. [Julie 9, prenarial wall, is remarkable on account of its outwardly long cylindrical character. In these respects, and in the absolute shearing out of the upper or nasal border of the maxilla, this bone in the Saiga is distinguishable from that of every living Ruminant. The antrum of Highmore, or sinus maxillaris, is very capacious, and the osseous walls altogether thin. A portion of it projects more than usual into the pterygo-maxillary and zygomatic fossa ; and this gives, when seen from the palate, a rounder figure to the fossa than obtains in ovine, caprine, or cervine forms. In the Chiru, Panthalops hodgsoni, an analogous inflation and extension of the postmaxilla is observable ; and it is further curious to note that both the Saiga and the Chiru are distinguished among antelopes on account of their nasal appendages. Regarding these and the enlarged larynx of Pallas's A. gutturosa, Turner remarks (P. Z. S. 1850, p. 168)-"These seem to be physiological adaptations, in no case marking a group, and therefore insufficient to warrant generic distinction, which has been made in the two latter instances." So far I agree with that meritorious author ; but had he seen the skulls, be would have found other distinctions whereon to base separation. The palatal plate of the palate bone (Pli), pierced by the posterior palatine foramen, is relatively large for a bovine. Behind it is broad and widely arching over the rounded front border of the posterior nares, gives much greater breath to this part than is found in the Antilopidae or even Ovida**; with its neighbouring plate of the opposite side, they, together crescentiform, reach forwards mesially to opposite the middle of the posterior lobe of the penultimate molars. As far as this latter disposition is concerned, it evinces leanings towards Sheep and Goats rather than Antelopes; moreover in Deer and Cattle these horizontal palatal plates in general pass to opposite a molar beyond the above. The very thin, moderately broad, yet remarkably deep, vertical pterygo-palatine plate of the Saiga, as in other ruminants, mainly forms the inner wall of the sphenomaxillary fossa, being strengthened moreover by the somewhat united stouter pterygoid process of the sphenoid bone. The opening of the posterior nares is two inches deep, and about one inch wide. Its open rounded palatine end is placed some distance behind the last molar. Thus in position it agrees with its hitherto believed ally the Chiru Antelope ; but in shape it disagrees, reverting to the ovine postnarial form. The anterior narial aperture of the Saiga, compared even with its own large posterior narial passage, is of excessive proportions, quite 1| inch across, and between 2 and 3 in depth; inferiorly the bone is smooth-surfaced. The slender columellar vomer (Vo), whilst vertically high, is remarkably short antero-posteriorly ; and its palatal attachment neither advances to the anterior narial aperture nor recedes to the posterior one. The spheno-rostral part, however, is well seen behind ; and in the live animal the anterior bony septal deficiency is made up for by cartilage and soft membranous substance. It is curious, though, that, excepting above, the vomer anteriorly is not grooved nor has everted lips, as is the rule in Ruminants. |
