204 HIROWO TTO 



intima is a thin chitinous membrane and is directly continuous 

 with that of the intestine. The basement membrane is a trans 

 parent structureless membrane surrounding the tube. 



The coelomic portion, which is provided with many fine 

 tracheal branches, is convoluted in the ventral portion of the 

 abdomen and ends blindly near the rectum. The distal end 

 of the tube is very fine, and measures about 0.05 mm. in diameter. 

 The epithelial cells are arranged in a somewhat peculiar fashion; 

 they are too large to admit of their forming a smooth lining, the 



Fig. 2 Surface view of coelomic portion from a total preparation. X 50. 



cell of one side projecting between two adjacent cells of the 

 other, so that the entire tube looks knotty, as is shown in figure 2, 

 and the individual cells are somewhat polygonal. The cyto- 

 plasm is granular or finely alveolar, and contains a great many 

 large vacuoles. The nucleus is stained deeply with haema- 

 toxylin, and some nuclei have already undergone fragmentation. 

 In such cases the chromatin comes together to form a mass. 

 The striated border is definitely recognized by its fine and closely 

 set striations, as is shown in figure 15. The lumen is irregular 

 in section, and is filled with spheroidal blue granules and yellow 



