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Show 1891.] MR. F. E. BEDDARD ON HAPALEMUR GRISEUS. 451 noted this fact without being aware of Dr. Dobson's observations, to which, however, I was able to refer in a footnote introduced after my article had been set in type. In the present specimen the diseased condition of the alimentary tract rendered these patches unusually clear, so much so that I have thought it worth while to have the accompanying drawing prepared ; this drawing (fig. 2, p. 452) will give some idea of their number and size upon one aspect of the colon. The strongly marked character of the Peyer's patches was due, Dr. Campbell informs me, not only to the pigmentation of the patches themselves, but to the anaemic condition of the alimentary tract. Ccecum. In my former paper I have described the csecum, but not the folds of mesentery by which it is held in position. These folds show an interesting series of variations among Lemurs, which appear to have some classificatory value. The csecum and adjacent parts of the alimentary tract of Hapalemur griseus are shown in the accompanying drawing (fig. 2, p. 452), which is of the natural size. Two folds (c and b) pass along the surface of the csecum nearest to the small intestine ; these folds run for a considerable distance towards the blind extremity of the gut, but do not reach it by a large interval. Both these folds bear blood-vessels, which ramify on to the csecum itself. The two folds are symmetrically disposed with regard to each other and the small intestine; they are quite free from the latter, passing by it on each side and uniting some way behind it with the mesentery which supports the small intestine. I found this arrangement in both the examples of Hapalemur griseus which I dissected, and therefore regard it as the normal condition. In Loris gracilis the disposition of these folds is quite different. I do not refer here to the shape of the csecum itself, or make any comparisons between different genera as regards their cseca. I merely call attention to the folds of mesentery. M y attention was directed to the possible importance of this anatomical feature after making myself acquainted with Prof. Flower's description1 of the corresponding folds in the New and Old World Monkeys. In Loris gracilis the two folds already described as existing in Hapalemur are also found; they are, however, more extensive, reaching nearly to the extremity of the csecum ; as in Hapalemur they bear the blood-vessels destined for the nutrition of the csecum. But in addition to these two folds, which evidently correspond to those of Hapalemur, there is a thin median fold, lying, that is to say, between the other two ; this fold is much less extensive, only reaching for a short distance along the csecum; it has no bloodvessels, and arises from the small intestine ; it forms a kind of web between the small intestine and the caecum. Nycticebus javanicus shows some differences in detail, as regards these points, from Loris gracilis, but resembles that species more closely than it does Hapalemur griseus. Three folds are present, 1 Medical Times and Gazette, 1872. |