(y 



1899.] OK A NEW CaUSTAOBAIf FROU LAKE TANGANYIKA. 697 



EXPLANATION OF THE PLATES. 



Plate XXXVI. 

 Trionyx suhplanus, p. 619. 



Plate XXXVIL 



Fig. 1 . Typhlops alhiceps, p. 654. Upper and side views of head. 



2. T. floweri, p. 654. Upper and side views of head. 



3. Cylindrophis rufus, p. 656. 



2. On a new Brachyurous Crustacean from Lake 

 Tanganyika. By William A. Cunnington, A.R.C.S.^ 



[Eeceived April 26, 1899.] 

 (Plate XXXVin.) 



The Crab described in this paper was obtained by Mr. J. E. S. 

 Moore, of the Eoyal College of Science, from Lake Tanganyika 

 during his visit in the summer of 1896. The specimens were taken 

 in fairly deep water — never less than 60, and from that to 500 feet 

 deep. I have had in all seven individuals to examine, of which three 

 are adult males, two adult females, and the remaining two young 

 ones. All these specimens, Mr. Moore informs me, were taken 

 in Kituta Bay, at the southern end of the Lake, but he has also 

 seen these Crabs near Kinyamkolo, also in the south, and Sumbu, 

 some 100 miles up the western coast. They are often found 

 clinging to iV^eo^^aMma-shells and other objects, and are very 

 active in habit. 



Their deep-water habitat is at first sight misleading; but a 

 careful examination shows that from the presence of a post-frontal 

 crest, and from the nature of the external maxillipeds, chelipeds, 

 and ambulatory legs, their characters are distinctly those of the 

 group of the Thelphusidae, in which, in consequence, they must be 

 placed, although at any rate the majority of its members are 

 mainly terrestrial in habit. 



The differences which Mr. Moore's specimens exhibit, however, 

 from any hitherto described form, are sufficiently great, I think, 

 to warrant the institution of a new genus for their reception. 

 I propose the name Llmnothelpliusa maculata for them, as sug- 

 gesting, in the first place, their habitat, and in the second their 

 characteristic spotted appearance. 



This being at present the only known form of its kind, it is not 

 easy to decide -which of its characters denote a generic distinction, 

 and which a merely specific, following, however, as far as 



^ From the Biological Laboratory, E. Coll. Sci. Lond. Communicated by 

 Prof. a. B. Howes, F.Z.S. 



