DOS i. IKEDA : 



structure of the uepliridial canals are m the main similar to those 

 of Caldwell, except in one important point, rlz., that the canals 

 are said to open ])y means of funnels into the collar cavity. 



When a larva of any type is examined in the living state, 

 the proximal ends of tlie organs are seen, as descriljed l)y Wageister, 

 as t\v(j bonquet-shaped masses which are formed 1)V a crowchng 

 together of the excretory cells (fig. 13, neph.). They are placed 

 symmetrically one on each side of the stomach and in front of 

 the postoral septum. Each of them consists of two ])arts, the 

 nephridial canal and the excretoiy cells. The former is com- 

 posed of a layer of cubical cells, and contains a narrow lumen 

 which ends l)lindly at the internal end and distal ly leads to 

 the nephridial pore lying on either side of the pouch pore. 

 The greater part of the nephridial canal, together with the excretory 

 cells, rests on the upper surface of the postoral se2)tum. Fig. 50 h 

 shows a cross section of the larva, passing through the left neph- 

 ridial canal near its internal blind end, where the excretory cells 

 adhere. In the above figure, a small cell mass inep.c) on the right 

 of the figure, shows the cut end of the nephridial canal which is 

 attached to the septum (//^e.s.). In the figure, the left canal {nepx) 

 containing a small lumen, is found applied to the somatic walls. If 

 traced a little downwards, these two canals become attached to and 

 imbedded between the two layers of the somatic walls, and are no 

 more to l)e seen in the collar cavity. Such a state is represented 

 in fig. 00 c, in which the two canals {ncp.c.) are wholly imbedded 

 in the somatic walls on both sides of the stomach {.siiii.). This 

 .condition is more distinctly shown in figs. 47 (a-c), which are 

 taken from serial longitudinal sections of a larva of type A with 

 12 tentacles. These figures sbow only one jujrtion of the skin, 

 where the nephridial canal and the somatic attachment of the 



