The Spermatogenesis io Pentatoma up to the Formation of the Spermatid. 13 



early spermatogonia, each group of cells would gradually increase in 

 size; while at the same time, owing to their increase in bulk they 

 would gradually be forced towards the distal end of the testicle. And 

 in the course of such a process, the connective tissue cells which form 

 the boundaries of these cysts, would likewise be pushed in the same 

 direction. This assumption would also explain how it comes to be 

 that the spermatocytes also are grouped into such cysts. 



The spermatogonia from the resting stage until about that time 

 when the monaster stage of mitosis is attained are found grouped in 

 radial clusters or rosettes around a point near the centre of each 

 spermatocyst (PL 1, Figs. 1, 5, 11, 14, 17, 24). The mass of cells 

 forming each such spermatogonic rosette is more or less spherical in 

 form; and all the component cells are connected at the centre of the 

 rosette. There is no elongated cytoplasmic rhachis, such as occurs 

 in Ascaris. Each cell has an approximately conical form, with its 

 narrower, pointed portion directed towards the centre of the rosette, 

 and its larger, rounded end at the periphery of the latter ; but unless 

 the section passes exactly through the central point of the rosette, 

 the radial arrangement of the cells is not apparent. The essential 

 peculiarity of these rosettes is that the cytoplasm of the cells of each 

 is directly continuous at the central point. Where such a cytoplasmic 

 continuity of the cells is found, gives assurance of the presence of 

 spermatogonic generations. But when the spindle is produced in 

 mitosis this central connection becomes interrupted, and each cell 

 becomes more spherical in form ; the cytoplasmic connection is not 

 resumed after mitosis. Tt is very probable that the formation of the 

 spindle is responsible for the separation of the cells from one another. 

 During this process no "residuary corpuscles" are produced. 



The resting spermatogonia (Figs. 1 - 4) are thus irregularly conical 

 in form. The cytoplasm appears rather dense, vacuolated in places; 

 the finely granular aspect it offers is of so delicate a nature, that it 

 cannot be determined whether it be alveolar or reticular. The cell 

 membrane is exceedingly delicate, thinner than that of the nucleus. 

 At the pointed end of the cell lies a spherical or oval body, homo- 

 geneous in appearance, which is stained more deeply by the action of 

 Hermann's fixative than the enveloping cytoplasm; it remains un- 

 colored by Hermann's stain, but with haematoxylin-eosin or with the 

 Ehrlich-Biondi stain it becomes a deeper red than the cytoplasm. 

 This body, which occurs in a somewhat different form in the spermato- 

 cytes, corresponds to that structure which has recently been the ob- 



