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Show 1880.] MR. W. A. FORBES ON THE UAKARI MONKEYS. 633 vertical. The perinseum measures about *35 of an inch. The ischi-atic prominences, perinoeum, and root of the tail are covered by greyish skin forming a rhomboidal space, about 1*5 inch broad and high ; under the tail there is a slight hollow, with a raised fold of skin at each side. The skin of the cheeks is thin and smooth throughout inside. The hard palate has about ten slightly curved (lunate) ridges on each side, best marked anteriorly, and not meeting mesially. The first two lie between the canines, the last on the level of the last molar. The more posterior ones are faint and irregular, and straighter; the two most anterior the strongest and most curved. In front of the most anterior are two small slits, one on each side of the centre, directed antero-posteriorly, and lying in a line with the inner margin of the median incisor. The tongue is elongate and parallel-sided, being bluntly squared off at the tip. In front of the palato-glossal folds, which are well developed, it is covered, above and on the sides, with filiform papillae ; below it is smooth. The fungiform papillae are numerous, and distributed over the sides and tip of the tongue in front of the circumvallate papillse ; of these there are four, arranged in the usual reversed A-shape, the extra one lying on the right side. In Pithecia satanas I found three only. There is a " Mayer's organ " of about 15 slits, in the usual position in front of the palato-glossal folds. There is a freenum linejuce, and a smooth, fleshy, well-developed sublingua, bifid apically, with the duct of the submaxillary glands opening on the two papillte behind this. The uvula is blunt and feebly developed. All the salivary glands are well developed. The parotid is large, measuring 2 inches across at its greatest development; it occupies part of the "anterior triangle," sending a lobe up and behind the auditory meatus ; it then runs forward over the masseter muscle, the superior border coinciding with the zygoma, as far as its anterior border, where on one side there is a small downwardly directed lobule developed. Below it extends far into the fossa behind the jaw, and is in contact beneath with the submaxillary. The duct opens opposite the last premolar. The submaxillary glands are also large; in contact with the parotids above, they nearly meet each other below. A few small accessory lobules appear superficially towards the anterior part. The glands are covered to a large extent by the jaw, running up on the deep side of the ascending ramus of the mandible, and covering there the digastric muscle ; at the angle of the jaw they appear superficially. The sublingual glands, well developed, extend back in the floor of the mouth for 1 inch behind the sublingua. On opening the abdomen, the great length and narrowness of the abdominal cavity are striking. The caecum occupies superficially nearly all the posterior part of the abdominal cavity, filling up thus nearly one third of the whole. Behind, it rests on the bladder, covering the rectum; its apex, directed downwards, lies in the right iliac region. The descending colon is quite superficial and lengthy, as is the ascending, which is also superficial, except in the middle ; the trans- PROC. ZOOL. Soc-1880, No. XLII. 42 |