14 HUMAN SPERMATOGENESIS: A STUDY OF INHERITANCE. 



The anterior region appears lighter because of some flattening, but especially 

 because it retains some droplets of karyolymph. 



During the spermiogenesis it seems to be impossible to distinguish the allo- 



somes. 



The karyolymph discharged from the nucleus composes at first a mass at or 

 near the posterior region of the nucleus (figs. 62, 63). This increases in amount 

 gradually, probably by further discharge from the nucleus, and its lateral contours 

 come to be bounded by a definite membrane (fig. 64 and the following), 

 then comes to encompass more or less of the posterior region of the nucleus, 

 never extending forward of the annular girdle, and to extend behind it usually 

 to the distal centrosome (Plate III). At its posterior border it does not appear 

 to be so sharply bounded as laterally, which seems to be due to its changing into 

 a hollow cylinder or cuff open posteriorly (fig. 92) ; but I could not determine 

 whether all its substance becomes arranged in such a hollow, open cylinder or only 

 its more peripheral denser part. No evidence was found that this cuff is at any 

 time composed of fibrils so as to produce a fibre-basket (Faserkorb). Within this 

 cuff both centrosomes generally lie, though sometimes the cuff does not extend 

 to them (figs. 71, 75, 77, 88). In later stages the cuff usually becomes more 

 indistinct, so that often only traces of its wall are to be seen (figs. 93, 95, 96, 

 Plate III; 103, 104, 106, Plate IV). The irregular bodies found within the cyto- 

 plasm in the later stages (figs. 95, 96, Plate III; 97-100, 102, 105, PI. IV), which 

 are probably comparable with the "tingirbare Korner" of the German writers, 

 may in part at least represent fragments of the cuff substance. But the cuff 

 disappears entirely before the maturity of the spermatozoon, its remnants being 

 thrown off with the abstricting cytoplasm. The latest persisting stages of the 

 cuff are shown in figs. 101, 103, 104, 106, of which the first represents an unusually 

 delayed persistence of it; with the final complete abstriction of the cytoplasm all 

 traces of it become lost . 



Thus the greater part, but not quite all, of the karyolymph, leaves the nucleus 

 to compose the cuff substance, which process accounts for the marked shrinkage 

 in nuclear volume; and the final abstriction of the cuff substance from the sper- 

 matozoon eliminates the major portion of the karyolymph from the cell. 



2. Centrioles, FlageUum, Cytoplasmic Structures. 



No trace of a sphere was found in the spermatids (nor in the spermatocytes) , 

 and no sign of a lance or perforatorium at the anterior end of the spermatozoon. 



In the anaphases and telophases of the second maturation mitosis (figs. 53, 

 55, PI. Ill) centrioles could not be discerned, and therefore are probably very 

 minute. They are clearly visible first at the stage of fig. 56, where two of 

 equal size are seen against the cell membrane. The outer one of these remains 

 always the most posterior and will be called the distal centriole (c.d.), the inner 

 one will be named the proximal centriole (c.p.). From this stage on a delicate 

 but deep staining flagellum is connected with them. Then the proximal centriole 



