222 
THE TANGANYIKA PROBLEM. 
have not yet been completed, and I propose to treat the 
whole subject fully here. It is also intended that the 
descriptions of the anatomy and the conclusions respecting 
the affinities of the halolimnic gastropods given in this 
Fig. 3. — Semi diagram of the anatomy of Typhobia Horei. The Mantle is cut 
open and the animal viewed from above. The nerves are represented in 
black, cryst. s., style sac, st., stomach, stn., gill. 
work shall be understood to supersede any others which I 
have already published. In what follows there will be 
found, in the first place, a description of the structure 
exhibited by each of the different halolimnic molluscs, 
and, in the second, a discussion of their affinities, based 
