OCCURRENCE OF AMITOSIS IN MONIEZIA. II/ 



one of the parts in such cases is " Nebendotter " falls to the 

 ground. 



As regards Richards' interpretation of " endogenous" division 

 (Child, I., p. 95), which he presents in connection with the case 

 of mitosis shown in his Figs. 17 and 18, it may be said that such 

 attempts at interpretation of another's observations are scarcely 

 worthy of criticism. The statement of an author that he has em- 

 ployed so far as possible every precaution and has repeated his 

 observations again and again to avoid error, is ordinarily given 

 some degree of consideration. Moreover, as regards this par- 

 ticular point I stated (Child, I., pp. 95-6) that "some cases of 

 this sort of almost diagrammatic clearness have been observed." 

 And finally reference to a few figures {e.g., I., Fig. 13^; II., 

 Figs. gA and gC) is sufficient to show that the parts in such 

 divisions are often very different in size and the membranes 

 perfectly distinct throughout. There is then not the slightest 

 basis for regarding them as misinterpreted mitoses. 



To sum up : Richards' evidence for the non-occurrence of 

 amitosis is wholly negative, my evidence for its occurrence is 

 positive. How far his failure to find amitosis may be due tO' 

 failure to examine the proper stages and how far to the actual 

 absence of such phenomena as I have described, it is impossible 

 to determine. Second, his attempts at interpretation of my results 

 as errors of observation are wholly unsuccessful, since they 

 concern stages of development very different from those on 

 which I have based my conclusions and occurring in another 

 genus, and since they involve a total disregard of much that I 

 have said concerning methods, precautions, the appearance of the 

 nuclei, etc. 



The whole question of the occurrence or non-occurrence of 

 amitosis is one which requires great care and extended research, 

 and it may be doubted whether it is a suitable subject for a 

 beginner in cytological investigation, both because of his lack of 

 experience and because he is likely to be guided to a greater or 

 less extent by the views of his instructor. 



I wish to add a brief remark concerning my later observations 

 on amitosis in other forms.* In this paper I merely recorded the 



1 Child, " Amitosis as a Factor in Normal and Regulatory Growth," Atiat. Anz., 

 XXX., II and 12, 1 907. 



