280 NATHAN FASTEN. 



commonly found associated with the spermatogonial strips 

 located in tubules where there are mature spermatozoa. These 

 so-called "nutritive cells" are huge structures assuming numerous 

 shapes. Typical examples are pictured in Figs. 3-7. The 

 delineation between the cells is oftentimes effaced, so that the 

 nuclei seem to lie in a syncitial mass of cytoplasmic material. 

 There is considerable difference of opinion amongst cytologists as 

 to the probable relation between the nutritive and spermatogonial 

 cells of decapod Crustacea. Grobben ('78), Gilson ('86) and 

 Herrmann ('90) look upon the nutritive cells as foundation 

 germinal cells from which the spermatogonia originate. In 

 contrast to this view, such workers as St. George ('92), and 

 Keppen ('06) regard the nutritive cells as being derived through 

 a transformation of spermatogonia which have not undergone 

 maturation. My own observations are in accord with the latter 

 view. Such stages like Figs. 3 and 4 resemble primary sperma- 

 togonial cells (Fig. i) but are larger in size. 



Many of the workers on the cytology of the Decapoda have 

 claimed that the nutritive cells undergo amitotic division. In 

 sectioned material it seems as if this were the case. For instance 

 certain sections through such cells as illustrated in Figs. 5 and 6 

 would yield typical examples for those advocating amitosis. 

 However, when smears of the entire cells were obtained, the 

 true condition is discovered. I have found numerous indications 

 that mitosis is the normal process of division in these nutritive 

 cells. A good review of the literature on this subject can be 

 obtained in my earlier paper on the spermatogenesis of the 

 American crayfish, Cambarus virilis (Fasten, '14). 



B. Primary Spermatocyte Stages. 



In the primary spermatocyte stages, the cells undergo growth, 

 synapsis and reduction in the number of chromosomes. A 

 single chromatoid body makes its appearance within the cyto- 

 plasm during the early stages of the growth period. The general 

 sequence of events is quite similar to that found in other decapod 

 Crustacea (Fasten, '14, '18, '24). 



Growth Period. The resting primary spermatocyte (Fig. 12) 

 is slightly smaller than the resting secondary spermatogonium 



