378 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



VIII. The Spermathecae. 



During copulation the spermatozoa of one worm are 

 transferred to the other, and stored in special organs 

 known as the spermathecae (PL I, fig. 2, sp.). In 

 Tuhifex rivulorum there is one pair of these organs 

 situated in the same segment as the testes, viz., in 

 segment 10. Their general form is best seen by liberating 

 them from the living worm. This can easily be done if a 

 mature worm be placed on a slide and a cover-glass put 

 upon it. The slightest pressure on the cover-glass is 

 usually sufficient to rupture the body wall in the region 

 of the reproductive segments, which are much 

 distended owing to the large number of spermatozoa 

 and ova developed. If the body wall be ruptured, the 

 spermathecae, which for the greater part of their length 

 lie freely in the body cavity, are usually forced out, but 

 remain attached to the worm at their external apertures 

 (PI. VII, fig. 49). The ease with which this operation 

 can be performed is due to the fact that the spermathecae 

 are of considerable length and are bent round in the 

 segment. They are also resistant to pressure, to some 

 extent, and as soon as the body wall of the worm is 

 ruptured they spring free. They are visible to the naked 

 eye in this condition as small, pear-shaped, opaque, but 

 glistening bodies, but it is necessary, of course, to 

 examine them under the microscope in order accurately 

 to describe their form. When examined thus, the whole 

 organ can be divided into two regions : — (a) a pouch or 

 sac-like portion (PI. VII, fig. 49, sp. p 1 .) which narrows 

 considerably to form (b) the duct opening to the exterior 

 near the ventral setae of segment 10 (PL VII, fig. 49, 

 sp. d.). 



The proportions of these two parts to one another 



