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Show 166 MESSRS. SCHAFER AND WILLIAMS ON THE [Jan. 18, gardens of the Society. This latter has been described (P. Z. S. 1875, p. 48) by Prof. A. H. Garrod, the Prosector to the Society, to whom we are indebted for the opportunity of examining the organ in question in these animals. Our original object was simply to record in general terms the differences in microscopic structure presented by those parts of the membrane which have a different appearance to the naked eye ; but since, in spite of recent researches, our knowledge of the minute structure of the gastric mucous membrane is still confessedly imperfect, it became obvious that it would be necessary to enter upon a minute examination of the several parts ; especially as they present very well-marked differences, and, in some cases, peculiarities of structure which tend to elucidate points yet in dispute with regard to the gastric mucous membrane of the higher Mammalia and of Man. As is well known, the stomach is, in the Kangaroo, a long sacculated organ not unlike the human colon; and the sacculations, as in that, are due to the presence of three longitudinal bands of plain muscular fibre, situate on the exterior underneath the serous membrane and shorter than the rest of the gastric wall, so that this is bulged out at intervals into sacculi separated by constrictions or inward folds of the membranous wall. One of the three bands is placed below along the greater curvature; and it is on either side of this that the sacculi are most marked; there are none at the lesser curvature, nor is the pyloric extremity sacculated at any part of its circumference. Besides the inwardly projecting folds between the sacculi, and which involve all the coats of the stomach, the mucous membrane shows the rugse ordinarily met with in a stomach not completely distended, and produced by contraction of the muscular coat. There are also in certain parts more minute folds, which would, no doubt, be effaced by complete distention of the organ, and which are probably due to a similar contraction of the muscular layer of the mucous membrane (muscularis mucosa). In the diagrams of the two stomachs which are here given, and in the accompanying general description, they are for convenience' sake treated as if they were more or less straight organs extending across the body from left to right as in the human subject, whereas in reality they are twisted upon themselves. A detailed description of the form of the marsupial stomach and its relations to other parts is, of course, foreign to the subject of the present paper, and must be sought for in recognized treatises on comparative anatomy *. * Tbe following are the dimensions of the organs as they appear after preservation in spirit:- Dorcopsis Macropus luctuosa. giganteus. , , ft. in. ft. in. Length along lesser curvature 10 18 Length along greater curvature, the sacculations not being taken into account 17 2 5 Length along greater curvature, reckoning in the sacculations 2 10 5 0 Greatest circular measurement 0 7 0 7 In both cases the stomachs were filled with partially digested food. |
