1891.] MR. F. E. BEDDARD ON HAPALEMUR GRISKUS. 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 ausemic condition of the alimen- 

 tary tract. 



CcECUin. 



In my former paper I have described the caecum, but not the 

 folds of mesentery by which it is held in jiosition. These folds 

 show an interesting series of variations among Lemurs, which appear 

 to have some classificatory value. The ctecum and adjacent parts 

 of the alimentarv tract of Hupalemur 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 caecum 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 caecum 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 e:xAm\Aei oi 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 caecum itself, or make any 

 comparisons between different genera as regards their caeca. I 

 merely call attention to the folds of mesentery. My attention was 

 directed to the possible importance of this anatomical feature after 

 making myself acquainted with Prof. Flower's description^ of the 

 corresponding folds in the New and Old World Monkeys. 



In Lvris gracilis the two folds already described as existing in 

 Hajmlemur are also found ; they are, however, more extensive, 

 reaching nearly to the extremity of the caecum ; as in Hapalemur 

 they bear the blood-vessels destined for the nutrition of the caecum. 

 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 caecum ; it has no blood- 

 vessels, 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 Gnisette, 1872. 



