Reis N\ Aer US. 
Worx LL: AUGUST, 1898. No. 4. 
THE MOLLUSKS OF THE GREAT AFRICAN LAKES. 
Mr. J. E. S. Moore has recently studied the Mollusk fauna of the 
African Lakes Nyassa and Tanganyika, and has recorded a portion 
of his results, which prove to be of very great interest.’ 
It is pointed out that the molluscan genera constituting the lake 
faunas of Africa fall into two catagories; those genera more or less 
widely distributed in Africa such as Unio, Spatha, Iridina, Corbic- 
ula, Limnea, Isidora, Planorbis, Ancylus, Ampullaria, Vivipara, By- 
thinia, Melania and their immediate allies, these constituting a per- 
feetly normal group, all or most members of which occur in most of 
the lakes yet explored. The second group comprises Typhobia, 
Nassopsis, Limnotrochus, Syrnolopsis, Tanganyicia, Bathanalia, Para- 
melania, Bythoceras and some other forms, and is confined to the 
single lake Tanganyika. This series of genera is called by Mr. 
Moore the “ Halolimnic group.” With few exceptions, they are 
deep water forms, mainly ranging from 200 to 1000 ft. which was 
the greatest depth reached, while the species of the “ normal” group 
of genera live mainly within the 100 ft. line. After a thorough 
discussion of the geological and biological aspects of the case, Mr. 
Moore concludes that the Halolimnie mollusks in Tanganyika owe 
their origin to an ancient connection with the sea. 
'Proc. Roy. Soc., LXII, no. 387, March 29, 1898. Quarterly Journ. Mic. 
Sci., XLI, pt. 1, p. 159, March, 1898. 
