24 J- E. WODSEDALEK. 



of attachment to the nurse cells and later to the discarded mass 

 of cytoplasm the heads of the spermatozoa increase somewhat 

 in size but retain the same staining capacity. The foregoing 

 facts seem to show beyond doubt that the developing spermato- 

 zoan derives nourishment not only from the nurse cells but also 

 from the cast-off cytoplasmic material. When the sperm reaches 

 maturity the acrosome disappears from view and the anterior 

 edge of the head becomes well rounded. 



In addition to the parts mentioned, there appears very fre- 

 quently a dense spherical" cytoplasmic mass represented in Figs. 

 67 to 75. As to the origin and fate of this body I am not entirely 

 certain. It seems, however, that it is a portion of the centro- 

 sphere, for in many of the early stages it was seen in the immediate 

 neighborhood of the small body which later forms the acrosome 

 (Fig. 67). Further evidence for this assumption is the fact that 

 the combined mass of these two bodies seems to be equal to the 

 size of the sphere in the stage immediately preceding (Fig. 66). 

 The consistency of this body, too, is similar to that of the 

 sphere. 



Figure 78 represents a mature spermatozoan of the pig which 

 appears rather simple in structure and form. The entire nucleus 

 of the spermatid has evidently developed into the head, which is 

 oblong and flat (Figs. 70-78). The nuclear material breaks up 

 into very fine particles which arrange themselves in a layer at the 

 entire periphery of the head wall (Fig. 77). 



With Heidenhain's iron-hsematoxylin the head stains a sort 

 of slate blue and is difficult to decolorize. A depression is present 

 at the posterior extremity which is in contact with a small 

 middle piece. The end-knob which is for some time attached 

 to the nuclear wall within the small depression (Figs. 74, 75 and 

 76) finally breaks loose and passes to the posterior extremity of 

 the middle piece, the greatest portion of which now remains very 

 clear in appearance. This clear area is similar in appearance to 

 the contents of the acrosome and one is led to believe that it is 

 due to the presence of the substance which was seen in form of a 

 clear sphere surrounding the centrosome after it emerged from 

 the centrosphere and persisted about the two centrosomes, 

 particularly around the inner one, after division (Figs. 66-69) 



