REPRODUCTIVE SYSTEM. 391 



it reaches this, however, the oviduct is associated with two 

 structures. The first of these is a long process, as long as 

 the common duct beside which it runs, in appearance 

 suggesting the flagellum, but expanding at its free end into 

 a globular sac the receptaculum seminis or spermatheca. 

 In Helix aspersa a long slender diverticulum is given off 

 from the duct of the receptaculum. This is also occasionally 

 seen in Helix pomatia. A spermatophore from anothei 



FIG. 211. Snail (Helix pomatia) laying its eggs. 

 After Meisenheimer. 



snail passes into the receptaculum, and is there dissolved 

 after some days, liberating hundreds of spermatozoa. By 

 these spermatozoa the ova of the snail are fertilised. It 

 seems likely that the place of fertilisation is in a small 

 diverticulum at the upper end of the oviducal side of the 

 common duct, whither the spermatozoa are said to find 

 their way. The second structure associated with the female 

 duct is a conspicuous mucus gland, formed of two sets of 

 finger-like processes. The secretion is very abundant 

 during copulation, and as it contains not a little lime, it is 

 possible that it may form the calcareous shells of the eggs. 



