2 3 o THE TANGANYIKA PROBLEM. 
kirkii by Miss Digby has fully confirmed the necessity 
for such a change, as the following account of her results 
will show. 
The shell of Chytra kirkii (Fig. n) is remarkably 
solid, closely resembling both that of Solarium and 
Xenophora. 
The animal is superficially like that of Typhobia , but is 
Fig. 13. — The nervous system of Aporrhais pes pelicani exposed from above for com- 
parison with that of Chytra , p. 232. 
modified in accordance with the peculiar shape of the shell, 
in the same manner as the animal of Xenophora. The 
teeth on the tongue are highly peculiar and closely resemble 
those of Capulus, even in minor details. The tentacles 
are long and slender, and the eyes sessile upon their 
outer bases. The snout is not long, and like that of 
