GAMETOGENESIS OF SACCOCIKRUS 89 



to form the mitochondrial tail-sheath (PI. 2, hg. 18 and 16). 

 The tail-sheath granules are seen at x in PI. 2, tigs. 11, 12, 

 and 14. 



9. Dm-ing these stages the Golgi elements tend to become 

 thrown downwards along the length of the sperm (PI. 2, tig. 16), 

 and this also occurs with the yolk-granules. In a bunch of 

 ripe sperms within the body of the male Saccocirrus small 

 granules are always found on the lower region of the sperm- 

 tails, and there seems to be good evidence that such elements 

 are derived from the Golgi apparatus (PI. 2, figs. 17 and 18). 

 If the receptaculum seminis of the female is examined, such 

 granules are also found on the tails of the sperms (PL 2, fig. 18, 



GAX). 



Fertilization. 



10. Saccocirrus is an example of precocious entry of the 

 spermatozoon into the unripe oocyte (PI. 8, fig. 22). The 

 nuclear head of the sperm alone enters the egg completely 

 at first, while the tail remains plastered on the surface of the 

 young oocyte (PI. 8, fig. 22, head at sp, fragments of tail 

 at spt). It is very difficult therefore to say whether these 

 sperm-tail fragments are or are not inside the oocyte cytoplasm 

 at this period. Later on, however, it is quite easily observed 

 that the elements of the sperm-tail do enter the egg, break up 

 further, and form large numbers of spherical granules (con- 

 secutive stages given m PL 8, hgs. 21, spt, 22, spt, 24, and 25). 



11. In many cases one cannot help believing that these 

 beads, derived from the remains of the sperm-tail, grow in 

 number and in size (cf. PL 8, figs. 28 and 25). 



12. These beads always remain in the periphery of the egg, 

 but do not seem to take any noticeable part either in the forma- 

 tion of yolk or in any process of fertilization. Careful examina- 

 tion of the periphery of many oocytes reveals the fact that the 

 granules are of two types, one going yellowish in OSO4, the other 

 going black, as shown in PL 8, fig. 21. It was thought that 

 the black granules might have something to do with the 

 black granules noted on PL 2, fig. 18, gax, which were con- 

 sidered to be derived from the Golgi apparatus. 



