214 ^ YRNES. [Vol. XV I . 



homogeneous appearance and becomes slightly granular ; at the 

 same time it also becomes more or less vesicular, as in PL XI, 

 Figs. 7 and 8. The sperm-head sometimes appears as a deeply- 

 staining mass of chromatin surrounding a clear central core. A 

 similar appearance of the sperm is often seen when the sperm- 

 heads are cut transversely in the follicles of the ovo-testis. 

 From these appearances, and from the absence of any definite 

 middle-piece to the spermatozoon, and also, as we shall see 

 later, from the usual absence of sperm-asters during the early 

 stages, the suggestion arises that the middle-piece may pos- 

 sibly be surrounded or overgrown, as it were, by the sperm- 

 head, so that the centrosome or centrosomes, if there be any, 

 come to lie within the nucleus. There is, however, no direct 

 proof of this. 



During the stage of the first maturation spindle small round 

 bodies are often found accompanying the sperm-nucleus, as in 

 PI. XI, Fig. 7, and PI. XII, Fig. 43. They are similar in size 

 to the large yolk-granules, but they stain very deeply like the 

 chromatin. They vary in number ; generally there are from 

 two to five of these bodies, but they are always found in the 

 immediate vicinity of the sperm-head. Small deeply staining 

 bodies similar to those in Limax are shown occasionally at the 

 periphery of the egg in Physa, but no function has been ascribed 

 to them. 



Foot has described granular bodies (" sperm-granules") which 

 accompany the sperm-head in Allolobophora foetida. In this 

 form the author ascribes their origin to the breaking down of 

 the original sperm-asters. In the fertilized ovum of Limax the 

 similar behavior of chromatin and of these tiny bodies toward 

 certain stains suggests that they may owe their origin to par- 

 ticles of chromatin that are constricted off from the sperm- 

 nucleus before it becomes vesicular. I have seen a few cases 

 in which a portion of the chromatin seemed to be in process of 

 constricting from the sperm-head, but such cases are not of 

 very frequent occurrence. After the extrusion of the first polar 

 globule these deeply staining bodies are rarely found in con- 

 nection with the sperm-nucleus. Still later they disappear, or 

 become scattered through the cytoplasm of the Q.%g, as in PI. XII, 



