70 



tine behind the typhlosolar portion resembles that described 

 as present in the right division of the straight intestine. 

 The wall may be smooth or thrown into three or four 

 longitudinal ridges. The whole surface is ciliated. The 

 oily eosinophilous globules already referred to are paiiicu- 

 larly abundant in the coiled intestine, and many may be 

 found lying freely in the cavity. The average diameter of 

 this portion of the intestine is about 0"5 mm. 



Towards the anus the epithelium becomes arranged in 

 a very peculiar manner (fig. 14, PI. III.). Passing over the 

 posterior adductor the wall becomes thrown into longi- 

 tudinal folds, which, towards the anus, become more 

 complex, secondary foldings being developed, and the 

 bases being narrowed till some folds have, in transverse 

 section, an almost dendritic appearance. Within they are 

 filled up by the dense tissue already noted. A continuous 

 sheet of connective tissue with a few muscle fibres 

 surrounds the gut, but does not enter into the folds. 

 Near the anus this dense filling tissue becomes restricted 

 to the dorsal half of the intestinal tube, where it forms a 

 crescentic pad lying on the epithelium beneath. This 

 epithelium differs completely from that forming the 

 ventral half. While the latter is thrown into complex 

 foldings and bears long cilia which, on account of the 

 proximity of the folds to each other, become matted 

 together in the lumen, the upper epithelium is smooth, 

 is non-ciliated, and consists of long clear spindle cells, 

 with nuclei lying at their lower extremities, which form 

 a sharp contrast with the cubical epithelium of the lower 

 half. The transition from upper to lower epithelium is 

 quite a sharp one. The tissue forming the pad lying on 

 the upper half of the tube differs somewhat from the 

 dense tissue lying outside the intestinal tube in its more 

 anterior parts. Here it seems to consist of a dense mass 



