CHAPTER XII. 
THE FAUNA OF LAKE TANGANYIKA. 
CRUSTACEA. 
The crustacean section of the fauna of Lake Tanganyika 
consists, so far as is at present known, of four conspicuous 
types. We have in the first place two genera represented 
by two species of aquatic crabs, Platythelphusa armata 
and Limnothelphusa metadata. The first of these was 
obtained by the French missionaries, and very briefly 
described several years ago by Milne Edwards in Paris. 
The second was acquired during the first Tanganyika 
expedition, being subsequently examined and described 
by Mr. Cunnington. Besides these crabs, there are 
two genera of prawns again represented by two single 
species — namely, Limnocaridina tanganyikee and Palcemon 
tnoorei, both obtained also during the first Tanganyika 
expedition. All these four species are peculiar to Tan- 
ganyika, and apparently do not occur in any of the 
other great African lakes. There are besides a number 
of minute forms present in the lake which are widely 
dispersed throughout Africa, but since there is nothing 
remarkable about these, and since they appear to be 
