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Show 1869.] ANATOIMY O F PROTELES. 485 have, unfortunately, not the materials at hand for a comparison with the larynx of an Hyaena. The thyroid bodies are unconnected with each other. Each is flattened, subtriangular, broad at the upper end, which reaches just above the lower border of the cricoid cartilage, and ending in a narrow tongue-shaped inferior prolongation. The entire length is 1"*1, the greatest breadth *4". The hyoid arch consists of the number of bones usual in the Carnivora. The basihyal is straight and narrow, nearly flat in front, rounded and slightly concave (from side to side) behind, expanded at the ends, *8" long. The thyro-hyals are slightly curved, thick at their basal, and flattened and expanded at their thyroidal ends, *8". The three bones of the superior cornu are of equal length, *6"; the distal, or that nearest the basihyal, is the stoutest, and has a prominent flattened expansion of the inner border, the edge of which is turned backwards ; and the whole bone has a considerable inward curve. The middle bone is simple, flattened, and slightly curved ; the proximal (stylo-hyal) is very slender, except at the extremities, slightly curved, and twisted upon itself. THORACIC VISCERA. The trachaea is 5" in length, and *55" in average width. It has thirty-six cartilaginous rings. It divides into two very short bronchi, which pass off nearly horizontally, and after a course of not more than -|" enter the roots of the lungs, each dividing into as many branches as there are lobes to the lungs. The right bronchus is rather shorter than the left. The lungs are deeply divided into distinct lobes-the right into four, the left into three. The mode of division is as follows : -A horizontal fissure separates each lung into two nearly equal portions ; the lower one, slightly the larger, has no further division ; the upper one is separated into two by a fissure running obliquely downwards and backwards from the middle of the anterior border to join the horizontal fissure near the posterior border of the lung; this separates from the upper a middle lobe, which is the smallest of the three. These divisions and lobes are almost exactly similar on the two sides; but the anterior margin of the left middle lobe has two deep notches, altogether wanting in the right. On the right side a distinct lobe (the "azygous lobe") is superadded, having no corresponding portion on the leit. It is triangular, about the size of the middle lobe, and placed on the inner side of the lung, its root being between those of the middle and inferior lobes. It lies to the inner side of the latter, behind the heart. This arrangement of the lung-lobes is that which obtains in the Carnivora generally. In the lungs of an Hyaena (H. striatal), No. 41, Stores, Mus. R. C. S., the divisions are precisely similar, except that the clefts on the anterior edge of the left middle lobe are wanting. The same is the case in the lungs of an Ileipestes. The heart is short and broad. The aortic arch, as usual in the |
