IO6 C. M. CHILD. 



and one that possibly does not always occur. The nuclei have 

 separated and between them there is a lenticular space appar- 

 ently empty, but probably containing fluid in the living condi- 

 tion. This space is apparently still intracellular for the cytoplasm 

 is clearly continuous across its ends. In most cases of amitosis 

 the two nuclei separate at one end first so that no such space is 

 formed. 



In Fig. 12, A and B, the same nucleus is shown at different 

 levels, A being the upper portion and B the lower. C is prob- 

 ably an early stage of amitosis. Both are from slightly later 

 stages of development than Fig. 11. 



Cases from a still later stage are shown in Fig. 13, AE. The 

 chain from which Figs. 10-13 were taken showed fewer mitoses 

 in development of all organs than any other examined. Mitosis 

 was scarcely ever seen in the ovary. That individual differences 

 do exist in this respect can scarcely be doubted. 



After the individual follicles begin to form, the divisions seem 

 to be more frequent in them, and especially near their tips, than 

 in the central portions of the ovary. Fig. 14, AD, show 

 groups with characteristic amitoses from the developing follicles 

 of J/. cxpansa. Fig. 15, A, and 15, B, are similar, the latter 

 showing a few nuclei from the extreme tip of the young follicle 

 not yet enclosed by a follicular membrane. In Fig. 16 the ter- 

 minal portion of another follicle is shown with three cases of 

 amitosis. 



An early stage in the development of the follicles in M. pianis- 

 simo, is shown in Fig. 17. The numerous cases of amitosis are 

 clearly visible. At a in the left follicle is what appeared to be 

 a group of small nuclei. It may be a multiple amitosis or may 

 possibly represent a stage in reconstitution after mitotic division. 

 The large nuclei in two of the follicles are frequently found along 

 the axes of developing follicles. One of them (<) is apparently 

 dividing into three parts. The nuclear divisions which have been 

 described thus far are in reality the oogonial divisions. The ami- 

 totic divisions certainly constitute a normal feature in the history 

 of the ova, as there is no evidence that the nuclei which have 

 divided mitotically have a different fate from the others. The 

 relative frequency of mitoses varies not only in different chains 



