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Show 1870.] DR. J. MUKIE ON SAIGA TARTARICA. 481 fering from that of other animals with a like nasal elongation, as notably the Pig, Horse, and allied Ruminants. The Tapir probably presents the nearest resemblance, minus lengthening and tactile apex; this, as has been shown, is chiefly owing to the shortening of the nasal bones and cartilages. Proceeding, however, with an enumeration of the parts from the superficial towards the deep, I shall state broadly that the muscles, vessels, and nerves closely assimilate in their disposition to those in the common Goat and Sheep; but the development of analogous parts does not quite correspond. In the Saiga there is a great broad sheet of muscular fibres which arise from the naso-, orbital, and maxillary regions, and, proceeding forwards, clothe the entire surface of the unusually vertically deep, nares (vide fig. 8, Na. m). Posteriorly the fibres are thin, but they acquire bulk as they go forwards and downwards. To the lower" border of the above, and, indeed, intimately connected with it, is a narrowed but also thick plane of muscular substance, which Springs: from the maxillary eminence and goes to the outer inferior side of the nostrils (z, fig. 8). Its direction is somewhat obliquely upwards or convergent to the first named. These two muscles respectively correspond to the levator labii superioris alceque nasi, and conjoined zygomatici. The lower one m a y also include the levator labii superioris proprius, whilst the upper one, in its deep transverse pale-coloured fibres, undoubtedly comprises the homologues of the pyramidalis nasi, compressor naris, and dilator naris. The last-mentioned three muscles, though most intimately interwoven with the coarser upper layer of the levator labii superioris aleecjue nasi, and in a manner inseparable from it, can yet be readily distinguished, as they are much paler in colour, finer in texture, and set obliquely or at right angles outwards to the narial wall. The alar cartilages, it is true, are situated far back ; nevertheless the posterior portion of the dilator naris (or levator proprius alee nasi posterior) is clearly present, filling the deep fissure between the maxillary bone and the curved tapering alar cartilage. The anterior portion of the dilator (levator proprius alee nasi anterior) abuts against the soft walls of the naris. The depressor alee nasi, and so-called naso-labialis of human anatomy, cannot be defined. In the Sheep and Goat the levator labii superioris alseque nasi is very small compared with the Saiga's ; and the other deep nasal muscles proper, from the cartilages being carried forwards, are very diminutive indeed in the former animals. The zygomatic and levator Jabii proprius muscles, however, are coequal, probably even thicker in the Goat, which, as a browser, as Ogilby remarks*, uses its upper lip to a remarkable extent. The trunk of the Elephant and Tapir, whilst absolutely composed of the same homologous elements, has quite a different appearance when cut into, either transversely or laterally. In them there is a vast accession of prominently marked muscular slips, and glistening interlacing cross fibres intermingled with large blood- * Trans. Zool. Soc. vol. iii. p. 58. |
