1399.] ON A IfEW CBTTSTAOBA.lS' FROM LAKE TAN-GANTIKA. 697 



EXPLAJ!fATION OF THE PLATES. 



Plate XXXVI. 

 Trionyx subplanus, p. 619. 



Plate XXXVII. 



Fig. 1 . Typhlops albiceps, 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. Oil a new Brachyurous Crustacean from Lake 

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



[Eeceived April 26, 1899.] 



(Plate XXXVIII.) 



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

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

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

 in fairly ^eep water — never less than 60, and fi'om 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 Kifcuta 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 Neothauma-&\\e\\^ 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-f I'ontal 

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

 and ambulatory legs, their characters are distinctly those of the 

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

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

 mainly terrestrial in habit. 



The diiferences 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 Llmnotheljphasa macidata for them, as sug- 

 gesting, in the first place, then 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 



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

 Prof. G-. B. Howes, F.Z.S. 



