238 DR. p. CHALMERS MITCHELL ON THE 



extreme distal end of the hind-gut was much expanded and 

 was followed by a narrower portion strongly sacciilated. I do 

 not attach much importance to this ; I have found the corres- 

 ponding region sacculated, apparently as an individual peculiarity, 

 in several examples of Lemurs and Monkeys, a,nd Dr. Beddard 

 (Beddard, 1908, p. 576) has recorded a similar but moi-e extensive 

 sacculation in the case of a Baboon. The distal portion of the 

 recurrent limb of the pendant loop gives rise to a long loop 

 (C.L.I in text-fig. 29, Cl.l in text-fig. 30) of which the proximal 

 and distal limbs are held together hj a very narrow expanse of 

 mesentery. This loop, lying just to the right of the representa- 

 tive of the transverse colon, corresponds with what is termed 

 the ansa coll dextra. Its presence as a defined narrow loop is 

 most marked in Chiromys and the genus Lemur. Dr. Beddard 

 states that it is absent in Microcehis (Beddard, 1908, p. 579), 

 and although I cannot agree with that author in making, in fact 

 or in theory, so sharp a distinction between loops that are 

 wide and loops that are narrow, I do agree that the ansa coli 

 dextra is absent in Chirogaleus. Dr. Beddard also attaches 

 importance to the fact that the ansa coli dextra is straight in 

 Chiromys and Lemur, and spirally twisted in Galago, Loris, 

 jSfycticebus, Indris, and pi'obably Perodicticus. As I have stated 

 already in this communication, I cannot follow Dr. Beddard in 

 attaching much importance to the presence of a spiral mode of 

 packing any portion of the intestinal tract, unless this common 

 growth-form attain a precise complexity. Nor can I agree that 

 the spiral of Lemurs can be taken as the rolling up of a defined 

 narrow loop. On reference to the original laboratory sketches 

 from which the diagrams of the patterns of Galago and Pero- 

 dicticus (Mitchell, 1905, figs, 41, 42) were made, and from 

 further observations made since, I find that the loop in question 

 may be very wide and irregular, presenting, when dissected out, 

 i\. number of minoi- loops, as in at least one example of Galago, 

 or two or more loops as in Perodicticus. These, however, are 

 folded against each other and against Meckel's tract, and rudely 

 twisted up. I agree, however, that it is possible to contrast 

 Chiromys and Lemur with other genera possessing a well-marked 

 ansa coli dextra, by saying that in the former the loop in 

 question is characteristically narrow and straight, and in the 

 latter that it tends to be spirally twisted. 1 should add to 

 this, that in the latter it also tends to be wider and more 

 irregular, and that the spiral twisting vai'ies considerably in its 

 extent. 



Immediately distad of the ansa coli dextra, whether that be 

 sti-aight or twisted, the recurrent limb of the pendant loop 

 I'eaches its highest point, and then, in the region corresjjonding 

 with the transverse colon, sweeps backwards to form the rectum. 

 The proximal portion of this gives rise, both in Chiromys and in 

 Lemur (text-figs. 29, C.L. 2 ; 30, CI. 2), to a well-marked loop 

 neither so long nor so narrow relatively as the ansa coli dextrco, 



