94 



PROCEEDINGS OF THE ACADEMY OF 



[March, 



stratification of the epithelium as mentioned by that author (Sadones, 

 Fig. 49) . The epitheUum covering the six longitudinal folds, although 

 it is not as well preserved in this region as one would wish, seems 

 to consist of a single layer of elongate cells. These, except for 

 the presence of more pigment, are similar to those described for 

 the folds of the first part of the hind-gut. The musculature of 

 the anal part of the Mecistogaster intestine is homologous, as is 

 pointed out below, to the musculature of the corresponding region 

 in Anisopterous larvae. 



Imcgt rmcgt ret 



dim, — , 



Icgt 



e 



rad 



e 

 ret 



rcgt 



rad 

 vim 



lit 



rlt 



Fig. 5. Part of photograph of transverse section 393 (Anal Part, or 

 Vestibule, of the Rectum). Enlarged 125 diameters. Abbreviations as in 

 Figure 1. 



Figure 5 is a photograph of section 393. It illustrates the 

 appearance of this sixth and last division of the hind-gut. In 

 section 393 the following parts can be made out: intima, i; pigmented 

 epithelium of the six longitudinal folds, e (the epithelium of folds 

 2, 6 and 10 is continuous with the more or less disintegrated epithe- 

 lium of the pigmented areas of the preceding division of the gut) ; 

 basement membrane, 6; reticulate connective tissue, ret; circular 

 muscle layer, an; and the radial muscle strands, rad. 



