| OCR Text |
Show 1870.] ANATOMY OF THE PRONGBUCK. 341 cell-structure of the medulla. The cell-walls are serrate ; as is but under a higher power, viz. 250 diameters, the transverse section, exhibited in C, brings out still further the markedly denticular character of each medullary cell. The finer hairs to which the term wool is applicable are depicted in D. The measure of modification contradistinguishing the hair of the antilopine, cervine, ovine, and hircine families is as follows. In Cuvier's Gazelle (Gazella cuvierii), which, for our comparison, may be taken as a fair type of what zoologists class as an Antelope, each hair has a proportionally thick cortex, and the medullar}' tissue is composed of minute, rather irregular-outlined, compressed cells, ranged transversely to the long diameter of the hair. In the Red Deer (Cervus elaphus) an equally good example of the cervine type, I find that, relatively to the calibre of the hair, the cortical envelope is only moderately thick, whilst the cellular medulla, in proportion to that of the Gazelle or Antelopes generally, is considerably increased. The medullary cells also have large, regular-sided, roundish or subhexagonal-contoured walls, not so squeezed together as in Gazella and its allies. In the Wapiti and other undoubted Deer an identical pattern prevails, the only obvious change being in the size of the cells, which slightly vary in different species. In all Sheep, with but slight specific modification, the hair shows a vast augmentation as respects medulla to cortex, the latter being very thin contrasted with the former. The cells of the medulla are much larger than in Deer, and preeminently so compared with those of Antelopes. Selecting the fleece of the Argali (Ovis ammon), as affording a fair example of the hair of the Sheep kind (and it is by no means an extreme instance), it demonstrates the said relative increment in the size of the cells and corresponding diminution of the wall cortex. In this ovine species the medullary cells, from a pure hexagonal contour, assume a tendency to an elliptical figure. In the Goats a form of hair-structure is mot with intermediate between that of Antelopes and Deer. Exemplifying the hircine |
