H. M. Morris 101 



1. The peritrophic membrane, which forms a thin- walled tube lying 

 loose within the stomach from the cardia to near the end of the 

 stomach. 



2. The epithelial layer is composed of cells with rather large and 

 dark-staining nuclei, and in some parts a distinct "striated margin" was 

 seen. 



3. The basement membrane, outside which is — 



4. The muscular coat consisting of poorly developed bands of 

 circular and longitudinal muscle fibres. 



5. The connective tissue, which lies outside the muscular coat. 

 The thickness of the epithelium varies slightly in different parts of 



the stomach, and it gives off protrusions into the cavity which are finely 

 granular, and feebly staining. 



From near the posterior end of the stomach a fourth caecum opens 

 on the ventral side. This caecum is smaller than the others and lies 

 parallel to the stomach with its closed end forwards. Its walls are of 

 a similar structure to those of the other caeca, but are considerably 

 folded near the attached end. The cells of all four caeca show a well- 

 marked "striated margin." 



The Hind-Gut commences in the ninth segment, but its length is 

 considerably increased by the formation of a loop. It is divided into 

 three parts, the ileum, colon and rectum (Text-fig. 9). 



The Ileum commences as a slight dilation, and is lined with a layer 

 of epithelium composed of rather large cells, slightly rounded on the 

 inside, and bounded by a fine intima. The epithelium rests on a base- 

 ment membrane, outside which is a strongly developed coat of circular 

 muscle fibres outside which again are longitudinal muscle fibres, the 

 whole being covered by a thin connective tissue membrane. The 

 circular muscles are very close together, each band touching those next 

 to it. At the commencement of the ileum the circular muscles are 

 particularly well developed. 



The Malpighian tubes are four in number, and at their attached end 

 they are dilated for a short distance to about twice the diameter of the 

 remainder of their length. 



The four dilated ends join together and join the anterior end of the 

 ileum by a short common duct, which Hes on the left of the alimentary 

 canal. 



The tubes are covered on the outside with a delicate membrane, 

 inside which is a fining of protoplasm containing numerous large nuclei 

 which bulge into the cavity of the tube. The nuclei of the dilated part 



