THE TANGANYIKA PROBLEM , . 
263 
The reproductive apparatus very much resembles that of 
Littorina , the genital gland occupies the upper part of the 
apical body whorl, and in the male is related to a simple 
vas deferens which opens at the extreme upper end of the 
mantle cavity. The opening is, however, prolonged as a 
ditch or groove, overhung by a flap, and terminates some- 
what forward on the body-wall. 
An exactly similar state of affairs is present in Littorina , 
and I found it also very well defined in the specimen of 
Faunus. In all essential details the female apparatus of 
Fig- 45- — Nervous system of 
Neothauma tanganyicense 
from above. 
