338 THOS. H. MONTGOMERY, 



takes intensely all chromatin stains. At its free end is a short, very 

 delicate thread which stains but faintly: this is probably comparable 

 to the so-called "Spiess" of other spermatozoa (S). The middle piece 

 is a short cylindrical rod (M. B), of narrower diameter than the 

 proximal portion of the head. The flagellum (Fl) is proximally of 

 about the same diameter as the middle piece, a slender thread several 

 times longer than the head, but how long could not be determined in 

 sections. With the triple stain of Hermann the head stains deep 

 red, the middle piece blue, and the flagellum faint lilac. 



VII. The Giant Spermatogonia. 



Under this provisional name will be described certain cells of 

 the testis, which do not appear to stand in the direct cycle of develop- 

 ment of the germ cells. 



These cells are found in the periphery of the testis, in the zone 

 of the spermatogonia, and even with a low power of the microscope 

 (such as obj. A, oc. 4) can be easily recognized by their large size 

 and clear appearance (Figs. 214—216, Plate 22; Figs. 217-227, 

 Plate 23). Their number varies in different testes. On one slide 

 containing 111 sections, 4 of these cells were counted; and perhaps on 

 an average one is to be found in every 25 or 30 transverse sections 

 of 6 /il thickness. Since in each cross section of the testis at least 

 two hundred spermatogonia are present, the number of the giant cells 

 is relatively a very small one. 



These cells lie among the spermatogonia, never in the sheath of 

 the testis, nor yet in the region of the spermatocytic divisions. They 

 show no relations to the fibre cells of the testis. But in the form 

 and number of their chromosomes they resemble the spermatogonia. 

 For these reasons they may be classed as spermatogonia, and as 

 "giant spermatogonia" be distinguished from the true spermatogonia 

 which produce the spermatocytes. 



All of the giant spermatogonia observed by me (and I have 

 studied at least 100) were in stages of mitosis. What is particularly 

 remarkable is that these mitoses represent stages from the late pro- 

 phase (the chromosomes in their definitive form and number) up to 

 the beginning of the anaphase (when the nuclear membrane is first 

 appearing); no cells of equal volume and appearance were observed 

 in earlier or later stages. Now where are the rest stages and early 

 prophases which surely should precede, and the anaphases which 



