3S4 MOLLUSC A. 



right side of the puhtionary chamber, and opening close 

 beside the anus. From two sources the kidney is supplied 

 with blood (a) from the pulmonary chamber, and {U) from the 

 heart by a renal artery. As in most other Molluscs, the 

 kidney communicates by a small aperture with that part of the 

 body cavity which forms the pericardial sac. Thus, as in 

 earthworm, lobworm, &c., the ccelome has a nephridial 

 connection with the exterior. 



Reproductive System. 



The snail is hermaphrodite, and its reproductive organs 

 exhibit much division of labour. 



(a) The essential reproductive organ (the ovotestis) is a 

 whitish body near the apex of the visceral spire. It 

 consists of numerous cylindrical folUcles, in each of which 

 both ova and spermatozoa are formed, but not at the same 

 time. Simultaneous formation of elements so different is 

 probably very rare. 



ib) A much convoluted hermaphrodite duct of a white 

 colour conducts the sex cells from the ovotestis, and leads 

 to the base of a large yellowish albumen gland. 



(c) This tongue shaped albumen gland varies in size with 

 the age and sexual state of the snail. It forms gelatinous 

 proteid material, which envelops and probably nourishes 

 the ova. 



{d) The ova and spermatozoa pass from the hermaphrodite 

 duct towards the head along a common duct, but not at the 

 same time. Moreover their paths are different, for the 

 portion of the duct down which the ova travel is much 

 plaited, while the path which the spermatozoa follow is a less 

 prominent groove, incompletely separated from the other. 

 Both paths are glandular, and the glands on the male side 

 are often called prostatic. 



{e) At the base of this common duct, a distinct vas 

 deferens diverges to the left and leads into a muscular /e«/i, 

 which can be protruded at the single genital aperture and 

 retracted by a special muscle. Before the vas deferens 

 enters the penis, a long process ox flagellum is given off. It 

 is hke the lash of a whip, and is as long as the common duct. 

 Within it a spermatophore is partly formed, but seems to be 

 completed in the penis. This spermatophore is laden with 



