OCR Text |
Show 1881.] MR. W. A. FORBES ON THE KOALA. 183 epigastric and left hypochondriac regions, the pylorus being directed towards the right side; and it is there in contact with the gall-bladder. The liver does not appear. The commencement of the transverse colon is visible, running downwards towards the left, below, but parallel with, the greater curvature of the stomach. The great omentum is attached to the transverse colon in the right hypo-chondrium, and does not cover the mass of the viscera. The greater part of the rest of the abdominal cavity is occupied by the great; longitudinally plicated, folds of the caecum and caecum-like ascending colon, a few folds of the small intestine appearing between the transverse colon and a great fold, apparently the caecum, which runs transversely across the middle of the abdominal cavity. On turning back these great superficial folds the end of the caecum is seen passing downwards to the left of the rectum, behind the uteri and bladder, to terminate, deep in the pelvic cavity, close to the cloaca! The descending colon, which is narrow and of the ordinary appearance, is very long, and is arranged on a broad mesocolon to the right of the vertebral column, forming here a series of loose loops, which, however, are not closely coiled together on each other as in Ruminants. The right kidney lies superficially to the liver. The duodenal loop passes downwards and to the right, and overlies the right kidney, but passes under the ascending colon just here. The stomach is cylindrical and sac-like. Its length, moderately distended, is about 3^ inches; its greatest depth, opposite the pyloric constriction, 1^ inch. There is a well-marked cardiac fundus to the left of the oesophagus, and the pyloric part is slightly bent on the cardiac part; this latter is marked off internally by a distinct fold of the mucous membrane, which is smooth and pale, with some slight traces of rugae in the cardiac fundus. The most marked peculiarity of the Koala's stomach is its possession, as is well known, of a special gland-patch, similar to that found in the Beaver ' and Wombat2. This gland-patch forms a slight elevation externally on the lesser curvature of the stomach, just on the pyloric side of the entrance of the oesophagus. It is somewhat saddle-shaped, with a transverse extent of 1*4 inch. Internally it forms an eminence about the size of a florin, which includes the entrance of the oesophagus. The mucous membrane on the gland-patch, around the entrance of the oesophagus, is red and vascular ; elsewhere in the stomach, as already stated, it is quite pale. The openings of the gland-patch are about 30 in number, of varying sizes, and irregularly arranged over the eminence. Some of the openings of the gland are complicated, several smaller openings debouching into a larger one ; and the area occupied by the openings is not symmetrical. The general appearance of this patch is well represented by Sir Everard Home's figure {I.e.) of that of the Wombat. In this latter animal the general structure and form of the stomach are also very like that here described; but it is more 1 Cf. Owen, Anat. Vert. iii. p. 422. a Home, Phil. Trans. 1808, p. S07, pi. ix. |