198 HIROWO ITO 



c. The coelomic portion. The epithelium is composed of a 

 single layer of two large polygonal cells. In cross-section, the 

 cell boundaries are not well defined. The cytoplasm, which 

 stains deeply with eosin, contains, near the striated border, 

 many large vacuoles which are undoubtedly secretion products 

 (fig. 4). Some faintly stained granular substance occurs in 

 the vacuoles. The nuclei are irregularly branched, as shown in 

 figure 1, and contain fine chromatin granules and nucleoli. The 

 epithelium of this portion never has the intima, but instead is 

 lined with a striated border, as has been observed by Schindler 

 (78), Bordas ('10, '11), Metalnikov ('08), and Veneziani ('03, 



cp ir 



cp cs 



Fig, 1 Surface view of urinary bladder (ub.) and common stem (cs.) and coe- 

 lomic portion (cp.) from a total preparation. X 20. 



'03 a, '04). The striated border is lightly stained and is marked 

 by many very fine and closely set striations. The lumen differs 

 in shape in different portions, and is filled with numerous granules 

 and crystals of various shapes, such as cubical, octahedral, 

 quadropyramidal, which are supposed to be made of a urate 

 salt, so far as my examination goes. The epithelial cells have a 

 very delicate transparent membrane which completely sur- 

 rounds the tubes. Muscles are entirely lacking in this region. 

 d. The included portion. In a cross-section of the rectum (fig. 

 6), lying inside the circular muscles, is a nucleated peritoneum, 

 which is a double layer, as has been described by Metalnikov 

 ('08), Ishimori ('16). Though it is very diffcult to make out the 

 exact course of the malpighian tubes in the rectal wall, it can 



