6 E. NOMÜRA : 



In young worms the clitellar hypodermis also consists of 

 regularly arranged, columnar cells like those of the extra-clitellar 

 part, and there is in addition a thin irregular layer of basal cells 

 between the superficial hypodermal cells and the circular muscle 

 layer. These basal cells later increase in height and assuming a 

 conical form, push outwards between the upper hypodermal cells 

 (fig. 2, A). In this stage of the clitellar development the sperm 

 cells are going through certain changes in the fully grown sperm- 

 sacs, while the ovaries yet remain in an immature state and none 

 of the ova are seen to contain yolk. When mature ova are found 

 in the ovisac the clitellar basal cells grow still taller and become 

 gland cells. With the full development of the clitellum, the 

 ordinary hypodermal cells are gradually compressed and become 

 finally filiform and fill the interspaces of the gland cells, being 

 merely supporting in function. 



The clitellar hypodermis of the present species is noteworthy 

 in having fine blood-capillaries developed in it. 



As Hatai does not appear to have observed the clitellum of 

 this species, I am of opinion that he worked probably only on 

 protandrously mature specimens. 



3). The circular and 



4). The longitudinal muscle layers are more or less richly 

 supplied with blood-capillaries and well developed in the anterior 

 part of the body. The longitudinal muscle layer is interrupted 

 and divided on either side of the body by the lateral lines into 

 the dorsal and ventral bundles. The longitudinal muscle fibres are 

 of different sizes and are arranged without any regularity, forming 

 apparently a single layer, as in most other tubificid oligochsetes. 

 The lateral lines begin at the front margin of the first segment and 

 reach backwards to the last one, running about halfway between 

 the dorsal and ventral setal fines on either side of the "body ; each 



