THE NEPHRIDIA OP LEECHES. 557 



and the ductules are very big. Wherever I have seen in 

 this region an appearance of a communication it has been 

 between the ductules and the duct, and that in very thin 

 sections and where the duct is obliquely cut. Sections and 

 fortunate fresh preparations show the ductules passing from cell 

 to cell so very clearly that if the alleged communications exist it 

 would probably be perfectly easy to see them. I still believe 

 that the system of ductules communicates with the duct at one 

 point only, the point marked g in my diagram. 



Since I join issue so completely with M. Bolsius in my 

 general conception of the organ, it is hardly worth while to 

 enter further into details; I have no doubt but that in some 

 minute points M. Bolsius has added to our knowledge of the 

 structure of the constituent cells of these organs, and it is a 

 pity in my opinion that he did not confine himself to such 

 matters. 



The funnel deserves a word or two, although M. Bolsius has 

 only given us as yet a detailed account of what he calls 

 " I'organe cilie" in Nephelis. M. Bolsius's attitude with 

 regard to the funnel may be gathered from the following 

 quotations : 



'' Pour nous, ces ' entonnoirs ' a I'extremite de I'organe font 

 defaut^' (Hirudo, Aulastoma). 



" Nous nions I'existence d'un entonnoir a rendroit indique " 

 (Clepsine, Nephelis). 



" La plupart de nos savants devanciers — Leydig, Lang, 

 Gegenbaur, Bourne — ont considere les organes cilies de la 

 Nephelis et d^autres Hirudiuees comme des entonnoirs 

 terminant leurs organes segmentaires du cote du coelom, et, 

 par suite, comme les homologues des entonnoirs bien connus 

 des Chetopodes. 



" En effet, I'analogie de ces diverses productions est 

 frappante et leur homologie morphologique ne parait pas 

 douteuse.'^ 



'' Mais si ces organes (les organes cilies) possedent chez les 

 Nephelis la meme signification morphologique que chez les 

 Chetopodes, ils presentent certainement chez ces etres 



