302 FERNANDUS PAYNE 



cells are narrower than the outer. At this inner end lies the 

 mass of mitochondrial granules. In the early growth period 

 these granules collect into a more or less spherical mass (plate 

 1, B). At this time several other bodies may be visible in the 

 cytoplasm (plate 1, B). The one which stains intensely black 

 is the chromatoid body. Its behavior has been described under 

 another heading. As to the origin, fate or function of the other 

 two bodies which look like plasmosomes, I have no data. When 

 the mitochondria at this stage are sufficiently destained, a plasmo- 

 some-like body can be clearly seen in the middle of them. What 

 this central body is, I am not prepared to say. Some observers 

 might call it an idiozome, but I am not inclined to do so, as 

 there is no indication of such a structure persisting immediately 

 after the spermatogonia! division. 



Following this stage the granular appearance of the mito- 

 chondrial mass changes to that of a mass of threads (plate 1, D). 

 This change seems to be due to the rearrangement rather than 

 to the fusion of the granules. The mass remains in this con- 

 dition throughout the rest of the growth period. Lewis and 

 Lewis ('15), in their recent observations of mitochondria in liv- 

 ing cells, maintain that a mitochondrium is an active moving 

 body, constantly changing its shape and position. Certainly 

 such cannot be the case here. At the metaphase of the first 

 spermatocyte division the threads take a position on the out- 

 side of the spindle, extending about half way round it (plate 

 1, E and F, side views and plate 1, G and H, polar views of the 

 metaphase plate). In side views, the threads appear as rows 

 of granules, and in polar views the cut threads appear as single 

 granules. After the chromosomes have reached the ends of the 

 spindle, the mitochondrial threads divide approximately in the 

 middle (plate 1, I). One mass of the divided threads moves 

 along the spindle toward one end of it and half toward the 

 other end. Plate 1, J, shows the mitochondria after they have 

 reached the ends of the spindle. In this figure they appear 

 granular again, but this I believe is due to the fact that the stain 

 is almost completely extracted. At any rate the threads are 

 present in the second maturation division. Their appearance 



