CHAPTER X. 
THE FAUNA OF LAKE TANGANYIKA. 
MOLLUSCA. 
The molluscan section of the fauna of Lake Tanganyika 
consists, as will have been seen from the lists given on 
page 138, entirely of gastropods and lamellibranchs. Of 
the latter group little can be said except that the number 
of distinct specific forms supposed to be related to the 
genus unto is somewhat remarkable. 
The gastropods, on the other hand, form a series which 
is nowhere even simulated, much less repeated, in any of 
the other fresh-waters of the world. We find, however, 
upon consideration of the lists of forms, that a number of the 
Tanganyika gastropods belong to genera which we might 
expect to encounter in the fresh-waters of any of the 
continents. To this normal series belong the following 
specific types : — 
Limn£ea debaizei Bgt. 
Isidora coulboisi Bgt. 
Physopsis africana Krauss. 
,, tanganyicne Marts. 
Flanorbis sudanicus Marts. 
Ampullaria bridouxi Bgt. 
,, ovata Ol. 
Lanistes jouberti Bgt. 
Vivipara trilirata Marts. 
Cleopatra guillemei Bgt. 
Bithynia humerosa Marts. 
Melania tuberculata Mull. 
,, tanganyicensis E. Sm. 
,, horei E. Sm. 
The nature of the genera containing all the above species 
is at the present time quite well known to naturalists, 
