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Show 1870.] DR. J. MURIE ON SAIGA TARTARICA. 501 sacculate the glandular portion of the skin of the groin. I at present clear regarding its homology ; but the better to call attention to the existence of this muscle, I propose temporarily to denominate it the invaginator sacculi. V. SYSTEMATIC POSITION OF THE SAIGA TARTARICA. When what is regarded among zoologists as an exceptional form, either in a family or genus, is put to the crucial test of anatomical detail, it is oftentimes hard to assign the creature a definite place, even when in possession of the more complete data. Such an animal is the Saiga! The difficulty in this as in similar cases springs mainly from two causes. One is the value to be attached to any single character or set of characters ; for upon this point the most conflicting views are entertained equally among the younger school of naturalists and among the older authorities. The other cause arises out of the circumstance that in most species such as that under consideration we have what the indefatigable embryologist Parker very deftly expresses in birds as " a generalized form," moulded akin to no special group, but, as it were, a combined patchwork of varied structural organization. The characters assigned by Pallas (I. c. p. 14) in his analysis of the genus Antilope* are, "Ant. saiga (cornibus distantibus, lyratis, pallido diapbanis, naso cartilagineo ventricoso)." Setting aside older and subsequent authors, I may mention that Dr. Gray t, with the addition to the above definition of its crumen (suborbital gland), distinct and soft fur, generically subdivided Saiga tartarica among the " Antelopes of the Fields " in his synopsis of the Bovidae. Mr. Turner"{:, in grouping the hollow-horned Ruminants from a study of their crania, unfortunately did not see a skull of Saiga. Provisionally, from the shape of tbe horns, that able anatomist placed it under Gazella, though animadverting upon Gray's generic separation because of their pale colour. The reply of the latter (Cat. B. M. 1852, p. 51) sufficiently answers the objection. This translucency of the horns, moreover, has even greater significance than their lyrate, annulated character, and, together with their occasional multiple number, decidedly evinces affinities to the Ovine type. Doubtless in size, shape, and position they conform to the Gazelles. So far, therefore, as outward aspect is concerned, they belong to the Antelope section, but not necessarily so ; for in the four-horned breeds of Sheep, and even in some of the two-horned varieties (e.g. the Wallachian Ram), these organs to a certain extent assume the said peculiarities. When the skeleton comes to be considered, the skull, as rightly interpreted by Turner in other Bovidae, affords distinctive marks of its family relationships. Whilst exhibiting structural formation pe- * See Ogilby's critical remarks thereon, Trans. Zool. Soc. vol. iii. p. 38. t Ann. & Mag. Nat. Hist. (1847), vol. xviii. p. 227. j P.Z.S. 1850, p. 168. |