THE NEPHRIDIA OF LEECHES. 559 



tion, the communication between tlie lumen of the tubules 

 and the coeloraic sinus seems to have been obliterated " 

 (Hirudo). 



" The nephridium, then, in all cases opens into coelomic 

 space on the one hand, and to the exterior on the other." 



These extracts speak for themselves ; the last of my state- 

 ments above quoted presupposes a little imaginative power in 

 the reader. The funnel is for me a part of the nephridium, and 

 it does open into the coelomic space ; but the communication 

 between its lumen and that of the nephridial tubules is, 

 generally at any rate, obliterated. That this structure may be 

 called a funnel will, I think, be admitted by every one who 

 knows that we use the word " funnel " in English in a mor- 

 phological sense ; and the desirability of calling it a funnel if 

 one thinks as I do, and as M. Bolsius does, that it is the 

 morphological homologue of the Chsetopod funnel, must be 

 obvious to all who wish to make their researches upon a 

 special subject of use to zoologists generally. M. Bolsius in 

 his account of the anatomy of the nephridia flatly denies the 

 existence of a funnel to these organs, and then proceeds to 

 write a special paper (5) upon it, only under a different name. 

 This is an example of M. Bolsius' method of writing; it is a 

 misleading method. 



The funnel is always (in the genera with a compact nephri- 

 dium) placed close to the " extremity " of the nephridium, 

 though not always perhaps in actual anatomical connection 

 with it ; and the striking point, the point which it is desirable 

 to emphasise, is that this fuunel, always in relation with the 

 " extremity ^' of the nephridium, occupies such a different 

 position in the various Hirudinean genera; it lies in the 

 ventral sinus in Clepsine, in a special sinus in Pontob- 

 della, in a special sinus of a different nature in Nephelis, 

 and in a (potential) peritesticular sinus in Hirudo. 



The funnel has in most genera, at any rate, lost its original 

 function, and M. Bolsius puts forward two hypotheses with 

 regard to its new fuuctions. I can express no opinion with 

 regard to the second of these without further research ; but if 



