48 J. F. McCLENDON. 



some of these groups, each of the cells becomes filled with an 

 achromatic substance which presses the chromatin and proto- 

 plasm against the cell wall. This substance increases greatly in 

 quantity and becomes more and more like yolk (called Austreibe- 

 stoffby C. Heider, '79). In very rare cases in some very young 

 spermatids I have seen a small achromatic sphere in the cyto- 

 plasm and have found a still smaller sphere in the cytoplasm of 

 some primary spermatocytes. On the other hand the substance 

 in question at first appears to lie within the nucleus and is closely 

 surrounded by chromatin. A plausible explanation might be 

 that the small globule seen in some very young* spermatids 

 moved up to and indented the nucleus, there growing until it 

 became larger than the original nucleus yet I have been unable 

 to find steps in such a process, in fact I believe the substance 

 arises in the nucleus.* The cells containing these spheres nourish 

 the spermatozoa, and may be called nutritive cells. 



Going back to the spermatids, many groups degenerate, be- 

 coming much shrunken, while those that will form spermatozoa 

 collect into larger groups, the cells of which begin to elongate 

 radially. As the spermatids become longer they come to lie 

 nearly parallel. The nucleus elongates into a spindle shaped 

 deeply staining fiber, covered by a thin layer of achromatic sub- 

 stance. The remaining protoplasm fuses with that of adjacent 

 spermatozoa and forms a mass in the center of the group. These 

 groups sometimes lie with one end against a nutritive cell, and 

 when the groups break up the spermatozoa collect around nutri- 

 tive cells until the cytoplasm of the latter disintegrates and the 

 chromatin collects into rounded masses that float about, leaving 

 only a sphere of a yolk-like substance, the achromatic substance, 

 which has now developed an affinity for plasma stains. As the 

 elements pass down the vas deferens the nutritive spheres lie 

 near its walls and on reaching the spermatophore the nutritive 

 spheres (Austreibekorperchen) form a layer several spheres 

 deep, and become pressed together into polyhedrons. Most of 

 the chromatic spherules form a layer within the nutritive layer but 

 some chromatic spherules caught between the nutritive spheres, 



* Compare formation of " Glanzkorper " from the plasmosomes of Pelomyxa : 

 Goldschmidt, Arch. f. Protistenkunde 5, p. 130. 



