No. I.] SPERMATOGENESIS OF BATRACHOSEPS. II 



plasm, aster, etc., generally containing the archosomes. The 

 spheres when perfect are differentiated into an inner and an 

 outer sphere, and at times also the outer sphere is further dif- 

 ferentiated into two distinct zones (Figs. 8, 9, etc.). The word 

 "differentiated" is used in the same sense as separated and 

 is not intended to indicate that the two spheres are differen- 

 tiated from the same kind of protoplasm. The inner one of the 

 spheres is the most distinct and also the most permanent of 

 the two. It is more constant as to form, and is characterized 

 by a capacity to stain much deeper than any part of the outer 

 sphere. It is also during a part of its life cycle well defined, 

 having then the form of a concave disc, or a mulberry-shaped 

 body, one side of which is strongly concave, while the other is 

 more or less noticeably convex (Figs. 12, 29-31). 



There is reason to believe that this inner sphere is always 

 concave, but that the concavity of the sphere is only perceived 

 when the sphere is seen from the side (Fig. 12), the con- 

 cavity not being visible when viewed in the other direction. 

 The comparison to a mulberry is yet more justified by the 

 structure of the sphere. It is, when perfect, always composed 

 of a number of alveoles of almost equal size, and so arranged 

 that the wall of the sphere is just one alveole thick. The cav- 

 ity of the sphere is not an empty cavity, but is more or less 

 densely filled with granules, less distinctly arranged in alveoles. 

 At a certain stage in the activity of the sphere and the archo- 

 some this inner more loosely constructed part of the sphere is 

 drawn out, the archosome being at its top, forming a pointed 

 cone of less staining capacity (Figs. 28, 35-37). The alve- 

 oles are non-permanent structures and formed by the peculiar 

 arrangement of the granules composing the spheres. It ap- 

 pears as if these granules secreted some distinct substance, 

 and that this substance was held together by the closely ap- 

 proached granules themselves, thus forming a bladder-like alve- 

 ole surrounded by a membrane of granules. The development 

 of the spheres will be described in another place ; here it will 

 suffice to state that the inner sphere is during mitosis gradu- 

 ally dispersed, part of it being undoubtedly used up in the for- 

 mation of the central spindle. Similarly the outer sphere is 



