572 



lari media parte prorsus deficiente et re vera in lateribus colli solum 

 distincto, sento frenali distincte altiore discrepans. 



Latera capitis, corporis, caudae maris nigro - maculata , subtus 

 nigro-pul verulentus . 



Hab. Spec. 7 inter urbes Mogador et Marocco, unicum props 

 urbem Casablanca (comm. ill. Hans Simon). 



Francofurti ad Moenum, a. d. X Cal. Octobr. 1881. 



3. The body cavity and nephridia of Platyhelmia: 

 reply to M. Ed. Van Beneden. 



By E. Ray Lankester, Professor in University College, London. 



It is impossible to carry on a discussion concerning what has been 

 written, when one of the parties who discuss refuses to look at that 

 written thing concerning which the discussion has arisen. I am un- 

 willing to occupy attention with what is after all simply an attempt to 

 correct a mis-conception of my views. M. Van Beneden and 

 M. Fraipont have attributed to me opinions which I do not hold and 

 which are not to be found in my writings. When I correct M. Frai- 

 pont's mistake in this matter, M. Van Beneden comes forward 

 and simply reiterates with a comical air of infallibility the false state- 

 ment which I had but just corrected in his pupil. At the same time 

 he makes a charsre against me similar to that which I found it neces- 

 sary to bring against M. Fraipont. Van Beneden says »Lan- 

 kester fait dire à Fraipont ce que ce dernier n'a ni pensé ni écrit. 

 Je ne sais ce qui a pu faire dire à Lankester: M. F rai pont 's 

 error consists in his attributing to me the view that the entire canal 

 system of the Flat-worms is to be regarded as coelom and only the 

 pore as excretory organ or nephridium«. 



This is really very strange, and necessitates repetition of what I 

 wrote on p. 309, of No. 85 of this journal. Immediately before the 

 words quoted from nie by Van Beneden, the reader will find that a 

 quotation of Fraipont's words is given which constitute as any 

 one might suppose that »qui a pu fait dire etc.«. The words of Frai- 

 pont are »il (i. e. Lankester) considère l'appareil excréteur des 

 Trematodes et des Cestodes comme homologue de la cavité du corps 

 des autres vers«. I protest in reply to this that (whether rightly or 

 wrongly) I do not consider the excretory apparatus of the Trematods 

 and Cestods as the homologue of the body-cavity of other worms and 

 that I never did so consider that apparatus. I considered (as I shewed 

 by citations in my article published in No. 85 of this journal) a pro- 

 ximal portion of the apparatus (as much as might represent in actual 



