264 J. E. S. MOORE. 



ultimately separate, passing in opposite directions towards the 

 relatively colossal centrosomes now occupying the spindle 

 apices (figs. 12, 17, 19, c, d). I have separated the dictyosomes 

 from the centrosomes, not because they appear to be in any 

 way essentially distinct, but because they originate at a later 

 period in the division, and the two sets of structures might 

 otherwise be confused. 



Respecting the relation between the pseudosomes, centro- 

 somes, and dictyosomes I shall speak later on. 



The two nuclear groups now separate as in fig. 14, and the 

 first reduction division is completed. The small elements thus 

 formed never again regain the character of a resting celV ^u* 

 there are appearances of irregular division, resulting in the 

 formation of two excessively small spheroidal bodies, each 

 presumably containing the equivalent of five chromosomes 

 (figs. 15, 16). This procedure must be looked upon as con- 

 stituting the second " Reduction Theilung," and the resulting 

 elements are the mature spermatozoa. 



With the above broad facts of spermatogenesis kept well in 

 view I proceed to a more minute description of the successive 

 stages of the karyokinesis related to it, more especially with a 

 view to determining the nature of the bodies I termed dic- 

 tyosomes and pseudosomes in the previous description, and 

 which at first seemed to appear, disappear, and reappear in a 

 quite bewildering fashion. The original small spermatocytes 

 are similar in all essentials to the least specialised elements of 

 the somatic tissues. 



When stained with orange, gentian violet, or hsematoxylin, 

 after treatment with Hermann^s or Flemming's fluid (the best 

 results were obtained from a combination of gentian violet and 

 orange), the somewhat triangular cells^ present a fine reticulate 

 appearance, both within and without the nucleus. The meshes 

 of this reticulum are of fairly equal size in both cases (fig. 1), 

 and a close examination leaves no doubt that the appearance 

 (at any rate in these cells) is produced by a vast number of 



* Compare vom Rath and Ishikawa, loc. cit. 

 2 Compare vom RatL's figs., loc. cit. 



