280 
THE TANGANYIKA PROBLEM. 
quite well known, 1 have not dealt with them in the pre 
sent work.* 
Limnothelphusa maculata was found in the deep water o 
Tanganyika, and the particular specimens examined and 
described by Mr. Cunnington were obtained to the south 
and west of the lake in water varying in depth from 500 
to 600 feet. They were brought up in the dredge 
clinging to Neothauma shells and other objects, and 
were very active. I have, however, obtained the crab 
throughout the lake. 
Platythelphusa armata was obtained by me only off 
the west coast of Tanganyika in nets and dredges 
which were being worked in water of about 20 fathoms. 
The prawns were found occasionally throughout the lake, 
and in the following descriptions of the above specific 
types I have but slightly adapted the material contained 
in the papers of Messrs. Cunnington, Caiman and Milne 
Edwards. See bibliographs of expeditions at end of 
volume. 
Limnothelphusa maculata + (Fig. I.). 
Regions and sutures on carapace moderately marked. Postero-lateral regions 
exhibiting an irregular series of small, slightly oblique and granular ridges. Post- 
frontal crest distinct, with median notch and partial lateral interruptions, but not 
extending to margins. Antero-lateral margins shorter than postero-lateral, armed 
with 2-3 spines, in addition to that at the outer angle of the orbit. Second joint of 
antenna extending to under border of front, and bearing a short flagellum. Cheli- 
peds in the male unequal, subequal in the female ; merus rather short, trigonous, 
with spine on outer margin ; carpus with two spines on inner margin. Ambulatory 
legs rather long and slender. Colour (in spirit) light yellowish-brown, with dark 
brown or reddish spots. 
* It should be noted further that the same species of Thelphusa which are found 
about the shores of Nyassa and other great African lakes, occur also about Tanganyika, 
but since these crabs are practically terrestrial, I have omitted them from the Tangan- 
yika list. 
t Cunnington, “ Prc Zoo. Soc.,” Part III., 1899, p. 698. 
