562 REVIEW. 



M. Bolsius were in the habit of examining organisms whole, 

 and living under the microscope, instead of at once plunging 

 them into Gilson's fluid and cutting sections of them, he 

 would, I think, never have committed himself to the theory 

 that the funnel assists the circulation in any appreciable 

 degree. In the first place the ciliary currents tend to drive 

 particles into the funnel, and in the second place every con- 

 traction of the body-wall in these and such like animals 

 causes more commotion in the coelomic fluid than fifty of such 

 funnels in a row would do. 



I now turn to M. Bolsius' account of the anatomy of the 

 nephridia in Clepsine and Nephelis, but I do not propose 

 to deal with these genera at length. My own observations 

 upon these organs in these genera were comparatively scanty, 

 but they were suflScient ; and I have recently fully confirmed 

 them, so as to convince me that M. Bolsius' account is abso- 

 lutely incorrect. According to M. Bolsius the organ has the 

 form of a ribbon composed of a single chain of cells. This 

 chain is perforated by three canals of unequal length. These 

 canals take their origin in the cytoplasm itself of certain cells. 

 The three canals unite in the inferior portion of the organ, 

 which contains a single lumen only. There is a much 

 reduced urinary vesicle. 



An examination of a small living Clepsine shows at once 

 the long loop with two ducts (e to/ of my diagram ; woodcut, 

 Clepsine), joining at either end a region with three ducts ; 

 and if a small Clepsine be macerated for twenty-four hours 

 in 10 per cent, nitric acid, and then washed and stained and 

 carefully teased, large pieces of nepliridium may be easily 

 isolated. I have just got out, for instance, the region where 

 the chain of cells coming from the funnel joins (at c) the heap 

 of cells through which the vesical duct runs, and the duct from 

 which my transverse section (e — f) is taken is clearly seen leav- 

 ing the same mass of cells at the same point. Neither of these 

 regions — which may be perfectly easily seen by the methods I 

 have mentioned — could find a place in M. Bolsius' scheme. I 

 have never worked out the whole course of the duct in Clep- 



