258 WALTON. 



After copulation, the amoeboid spermatozoon makes its way up to 

 the proximal end of the uterus before insemination can take place. 

 Here, as Wildman and others have showTi in A. megalocephala, it is 

 found that in about 90 per cent of the spermatozoa the refractive 

 bodies have degenerated, and often are entirely wanting (Figs. 13 and 

 14). As many spermatozoa completely lack the refractive body as 

 have it in a fully developed condition. That this appearance is not 

 due to a degeneration of the sperm is demonstrated by the fact that 

 more eggs were found penetrated by sperms in this condition than by 

 sperms having a fully developed refractive body. It seems to the 

 A\Titer that, as Marcus has hinted and Wildman definitely stated, 

 the function of the refractive body is not one of a mechanical suppcfPt 

 for the sperm head in penetrating the egg, but rather that of a source 

 of food during the long interval between copulation and insemination. 

 If this view is correct, the food of the spermatozoon is provided by the 

 extrusion of a nuclear substance in the early spermatocyte and a 

 building up of a food supply through the action of this material upon 

 the cytoplasm of the spermatocyte and of the spermatid. 



The 'Mitochondria.' 



With iron haematoxylin-Bordeaux red stain the plastosome and 

 other scattered nuclear granules take a red stain, while the karyosome 

 and its derivatives take a blue stain. These granules later (early 

 spermatocytes) disappear from the nucleus simultaneously with the 

 disappearance of the plastosome. At the same time similar granules 

 are found in the ' refringent vesicles ' and continue to show quite plainly 

 up to the time of the second division (Fig. 5). As Montgomery ('11) 

 has shown in Euschistus, the plastosome is of karyosomal origin; and 

 as the refringent vesicles of Ascaris are karyochondria, the statement 

 of Wildman, that the granules of the refringent vesicles are also of 

 karyosomal origin seems most probable. 



As mentioned above, at the anaphase of the second maturation 

 diAdsion, these granules are given off by the refringent vesicles as the 

 plastochondria. The majority of these granules gather in the peri- 

 nuclear space, but a large number of the smaller ones are also foimd 

 scattered generally throughout the cytoplasm of the cell (Fig. 6) and 

 hence are lost at the time of the 'cytoplasmic reduction.' Wildman 

 states that these granules fuse to a slight extent, but no direct proof 

 of this could be foimd in A. canis, although there are fewer and larger 



