228 



abandon the position of attributing to me, views which I do not hold 

 and have never held. 



It remains to induce M. Van Beneden to proceed further in 

 the rectification of his conceptions as to my views. At any rate I hope 

 that I shall be able to place the matter clearly before the readers of this 

 Journal, and may after this note, be allowed to abstain from further 

 discussion of the subject. 



M. Van Beneden having withdrawn one part of his erroneous 

 statement as to what he conceives to have been my views, now states as 

 follows, »Lankester professe l'opinion, partagée d'ailleurs par tous 

 les helminthologistes de l'époque , que chez un Trématode il n'existe 

 entre l'épithélium du tube digestif et l'épithélium tegumentaire d'autres 

 cavités que les canaux du système aquifère. Il émet l'hypothèse qu'une 

 partie de ce système de canaux représente le coelome, tandis que l'autre 

 représente le nephridium et cela sans chercher à déterminer la limite 

 entre les deux portions de l'appareil.« 



In reference to this I have to point out that I have never in rela- 

 tion to this subject spoken of the Trematodes alone but have consi- 

 dered the various groups of Flat-worms (viz. Planarians, Nemertines, 

 Trematodes and Cestodes) as one illustrating the other. M. Van Be- 

 neden insists that I knew of no other spaces between the intestine 

 and epidermis excepting those definitely recognised as the canals of the 

 .système aquifère', and he gives a woodcut here reproduced (A) to 

 illustrate what he would say must have been my conception on the 

 matter in order to contrast it with another (B) illustrating Fraipont's 

 results. 



S 





In the woodcut A which Van Beneden declares to represent 

 my view , he has drawn the nephridial canals as abruptly ending. 

 He has no justification for thus abruptly cutting ofi" these canals. It is 

 true that zoologists had no definite knowledge ten years ago of the 



