92 



is also of the same diameter and retains this until the 

 pointed extremity is reached. 



The " worm-like " spermatozoa (fig. 57, c) are 

 rather wider and shorter than the " hair-like," and the 

 region of greatest diameter is near the anterior end. No 

 differentiation can be made out except that the cytoplasm 

 possesses a number of granules. Retzius states, however, 

 that in macerated preparations a long fibre can be seen 

 running down one side from end to end. 



The vas deferens is lined by ciliated cells, and in the 

 reproducing season is filled with spermatozoa, any cut 

 causing a white milk-like fluid to ooze out. 



The Female Gonad occupies the same position as that 

 of the male, and running along its right and ventral side 

 is the oviduct, which lies in very much the same position 

 as the vas deferens in the male, and begins by being an 

 extremely small canal. It is very different, however, 

 from the male duct in being perfectly straight without 

 the peculiar windings (fig. 55, OvdJ), which seem to be 

 characteristic of the male gonoducts. One meets with the 

 same convoluted vas deferens in other groups of animals. 

 It is probably due to the fact that development of the 

 spermatozoa takes place after the spermatocytes have 

 been cut off from the epithelium, and also to the absence 

 of any large storing organ for the spermatozoa. The 

 oviduct is a narrow tube with delicate walls. In fact, it 

 resembles a large blood vessel, running along the right 

 side of the digestive gland close to the surface (fig. 55, 

 OvdJ). At a point below the renal organ, it turns abruptly 

 at right angles, and immediately takes on a very different 

 structure (fig. 55, Ovd."). The walls at once increase in 

 thickness until the tube forms a cylinder about \ an inch 

 in diameter. The walls of this are, right and left, about 

 \ inch thick, and the lumen in section is a long crescentic 



