742 PR(3CEEDINGS OF THE ACADEMY OF [Oct., 



The females are impregnated with sperm, and the receptaculum 

 seminis filled with a great mass of it, before the ovocytes enter the 

 uteri, so before the first polar spindle is formed. This I have proved 

 by examination of numerous adult females. There is an intimate 

 coition, the male placing his cloacal aperture against that of the female ; 

 and the sperm has to traverse the length of the cloaca before reaching 

 the receptaculum. Ova will apparently not develop unless fertilized, 

 for there was no development at all in the egg-string of a female whose 

 receptaculum was without spermatozoa. In the testes of the adult 

 male only mature spermatozoa are present, and in this species there 

 appears to be no spermatophorcs. 



When the ovocytes reach the atrium they become surrounded by 

 the minute flagellate spermatozoa issuing from the receptaculum, 

 and in the posterior part of the atrium and the proximal end of the 

 cloaca the sperm enters the egg (fig. 6). The pole spindle is now ex- 

 centric; the spermatozoon enters usually at a point of the periphery 

 furthest removed from the spindle, but sometimes quite near it (fig. 

 6). On strongly destained hsematoxyline preparations the spermato- 

 zoon head is sharply distinguishable. The ovocytes are propelled 

 backward within the cloaca compacted into an egg-string. While the 

 ovarian egg has a limiting membrane of very delicate nature, the egg 

 in the proximal part of the cloaca has a thicker membrane that stains 

 with hsematoxyline (fig. 6); this increases in thickness as the egg pro- 

 gresses backward and becomes the outermost envelope of the egg 

 (figs. 8, 10). At the posterior end of the cloaca each egg shows a 

 spermatozoon wathin the cell membrane, and the first polar spindle 

 at the periphery of the cell (fig. 8). At this stage the egg has two 

 membranes: the outer, thinner one staining with chromatin stains, 

 already mentioned, and a thicker inner one that stains faintly with 

 cytoplasmic stains (fig. 8) ; both are closely adherent to the cytoplasm. 

 But where the polar spindle touches the periphery these membranes 

 are not present. It is probable that both these membranes are pro- 

 ducts of the cytoplasm, and not of any gland cells of the genital passages 

 (as I had previously opined), else one could not explain their absence 

 in the region of the polar spindle. The outer membrane has at its 

 inception probably a glutinous nature, serving to hold the eggs 

 together in a string. 



The eggs pass out of the cloaca in a cylindrical continuous string, 

 usually much convoluted, and in the first few days snowy white; the 

 worm may occupy as much as twenty-four hours in the discharge of 

 its egg-string, and then, with its body flaccid and flattened, it expires. 



