DEVELOPMENT OF THE CAPE SPECIES OF PERIPATUS. 469 



familiar with, as is shown by his constant reference to them — 

 do these openings give rise to the mouth and anus of the 

 adult, or do they become closed up, the mouth and anus being 

 new formations? 



Balfour was unable to settle this, because he had no embryos 

 between Stages b and r. The presumption was that they did 

 not, both of them, persist, because Moseley (No. 23 a) had 

 stated that he could find neither mouth nor anus in his 

 youngest embryos (about my Stages d and e). Dr. Kennel 

 was acquainted with this statement by Moseley, as is shown 

 by his remarks on p. 195 of Part I of his work, where he 

 actually uses it to cast doubt upon my view that the mouth 

 and anus of the adult are derived from the blastopore of the 

 embryo. There can be no doubt then that Kennel knew that 

 Balfour had not proved the thesis that the mouth and anus of 

 the adult were derived from the two parts of the blastopore. 

 The intermediate stages which were necessary for its proof 

 were obtained by me a year later, and I first announced the 

 fact that the two parts of the blastopore persist into the adult, 

 in my paper on the "Origin of Metameric Segmentation,'' in 

 a passage which reads as follows (p. 55): "In the paper referred 

 to (Balfour's memoir, edited by Moseley and myself) the ques- 

 tion — Do these two openings become the mouth and anus of 

 the adult ? — was left open. I am now in a position to state 

 that they do become the mouth and anus of an embryo of an 

 age equal to the oldest stage described by Moseley in his 

 original paper, so that I think there can be no doubt that they 

 do become the mouth and anus of the adult." 



Dr. Kennel brings another charge against me of the same 

 nature, equally baseless and wanton. 



I believe Dr. Kennel to be an honest worker, and I do not 

 wish to speak of him in an unnecessarily harsh manner, but I 

 am bound to confess that I do not understand his attitude of 

 mind in bringing charges of this kind against me. I need 

 only say with regard to them that the accusation of plagiarism 

 in the matter of the mouth and anus may be taken as a fair 

 sample of the kind of criticism, if criticism is the word 



