174 c - M - CHILD. 



tainty, but the observations seem to indicate that they may. The 

 relative frequency of the two processes, typical maturation and 

 fragmentation, appears to vary in different chains, proglottids, and 

 regions. In some chains typical maturation has been observed 

 only rarely, and fragmentation very frequently in the testes, yet 

 these chains apparently produce as many spermatozoa as others ; 

 in some proglottids of certain chains the maturation-phenomena 

 are similarly very infrequent while fragmentation is of common 

 occurrence, while in other proglottids typical maturation is more 

 frequent, and finally, in many proglottids the maturation-phe- 

 nomena have been observed much more frequently in those testes 

 which occupy the lateral regions of the proglottid, while frag- 

 mentation appears to be more characteristic of the testes in the 

 middle regions. 



The first cleavage of the egg is at least usually, if not always 

 mitotic, but in later stages amitosis becomes the characteristic 

 method of division, mitosis appearing only occasionally, and then 

 in the larger nuclei (Child, 'ojd ). Throughout the stages of 

 cleavage observed nuclear division is far in advance of cytoplasmic 

 division. 



In the development of somatic structures in the proglottid 

 mitosis is almost never seen, amitosis being the typical method 

 of division. When mitoses occur they occur as isolated cases, 

 usually at or near the periphery of regions of proliferation. 



If my observations are correct, amitosis is the more common 

 method of division in the generative cycle, except during the 

 period of maturation and early cleavage. In the somatic cells of 

 the adult body it appears to be the usual method at all times. 

 Later embryonic stages inhabiting the intermediate host are not 

 at present known, but conditions will probably be found to be 

 similar in these. 



Considering these facts in the light of the hypothesis presented 

 above, we find them in general in accord. In the first place 

 Moniezia produces rapidly an enormous number of generative 

 cells and this involves a very large amount of assimilation. 

 These, according to our hypothesis, are conditions favorable to 

 the occurrence of amitosis, and we have found that amitosis is 

 the characteristic method of division in the development of ovaries 

 and testes. 



