THE TANGANYIKA PROBLEM. 



26 



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 



Fig. 45-— Nervous system of 

 Neothauma tanganyicense 

 from above. 



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 



