264 
THE TANGANYIKA PROBLEM. 
Zonata repeats that of the male, but there is neither an 
external groove nor pouch. 
NEOTHAUMA, SMITH. N. TANGAN VICENSE. 
An examination of the animal contained in the remark- 
Fig. 46. — Nervous system of 
Vivipara from above. 
able shell to which Smith applied the name Neothauma, 
and some details of which I have already published in the 
Proceedings of the Zoological Society, has established the 
fact that Neothauma is a close ally of the genus Vivipara. 
It differs, however, from Vivipara in several details which 
are quite sufficient to allow the mollusc to continue to be 
