238 Prof. W. Salensky on the 



and contains a somewhat sparsely developed network of 

 chromatin- fibres. The expanded half of the kalymocyte con- 

 sists of coarsely granular protoplasm, in which, even in 

 freshly separated cells, one or two vacuoles are discernible. 

 In the kalymocytes which have migrated into tlie segmen- 

 tation-nucleus, the vacuoles increase in number as time 

 goes on. 



Most of the kalymocytes immediately after their formation 

 wander from their place of origin to different parts of the 

 oosperm. Some enter the yolk, move about there, and reach 

 the lower surface of the segmenting-nucleus ; the others 

 wander into the space between the yolk and the follicle-wall, 

 and finally arrive at the outer surface of the nucleus. Since 

 the two kinds of cells differ materially from one another in 

 form, I will deal with them separately. 



The migration of the kalymocytes into the yolk first begins 

 at the time of the segmentation of the nucleus, and reaches 

 its height at the period of the formation of the lower wall of 

 the mesenteron. We can convince ourselves, by examination 

 of successful sections, that immediately after the entrance of 

 the kalymocytes into the yolk they undergo important changes 

 in form, as well as in the constitution of their protoplasm. 

 They assume an Amoeba-like shape and are much less readily 

 stainable with carmine than the cells which lie on the wall of 

 the follicle. The alteration in the extent to which they are 

 affected by staining-reagents is probably due to the yolk 

 which they absorb by the way. In consequence of the 

 blanching of the protoplasm, the nuclei of the yolk-kalymo- 

 cytes appear much more distinct than do those of tlie kalymo- 

 cytes of the follicle-wall. The number of the kalymocytes 

 found in the yolk is very variable in the different ova. Some- 

 times we meet with a mass of star-shaped yolk-kalymocytes, 

 whicli are united together in groups by their pseudopodia. 

 The majority of the yolk-kalymocytes in their movements 

 tend towards the upper pole of the oosperm, that is to say in 

 the direction of the nucleus. We always find the largest 

 numbers in the neighbourhood of the surface of the yolk on 

 which the nucleus lies ; and since they invariably appear 

 most numerous at the time of the development of the lower 

 wall of the mesenteron, it is highly probable that they take 

 part in the formation of the latter. This conclusion is sup- 

 ported by the fact that, just at the point where the mesenteric 

 wall is in process of formation, the kalymocytes can very fre- 

 quently be observed emerging from the yolk. The liberated 

 kalymocytes undergo a change in form, flatten themselves 

 out, lose their pseudopodia, and range themselves alongside 



