Connection of Lake Tanganyika with the Sea. 451 



or to disprove, and the Antarctic holds for us innumerable problems 

 ot which we can foresee neither statement nor solution, as well as 

 the solution of those that we can already in some measure foresee. 



u On the Zoological Evidence for the Connection of Lake 

 Tanganyika with the Sea." By J. E. S. MOORE, A.R.C.S. 

 Communicated by Professor Lankester, F.R.S. Received 

 January 12, — Read January 27, 1898. 



(From the Huxley Research Laboratory, Royal College of Science, London.) 



Before 1896, when I had the opportunity of studying the fauna of 

 Lake Tanganyika on the spot, it was known that there existed in the 

 so-called Sea of Ujiji, oue animal, the affinities of which are undoubt- 

 edly marine. This was the medusa Limnocnida, which Dr. Boehm 

 saw as he crossed the lake in 1883. 



It was known further that the jelly-fish was associated in Tangan- 

 yika with a number of strange molluscan forms, for the empty 

 shells of what appeared to be some six entirely new genera of gaster- 

 opods, had been brought home by Captain Speke, Joseph Thomson, 

 and Mr. Hore. As the animals contained in these shells have not 

 hitherto been known, their classification by the conchologists with 

 existing fresh-water types has always appeared extremely doubtful, 

 and from the first Mr. Edgar Smith, who described the greater 

 number of these forms, has held the opinion that they might eventu- 

 ally turn out to have the same oceanic characters as the jelly-fish. 



It was therefore one of the objects of my recent expedition to 

 obtain material for the complete determination of these molluscous 

 types, and especially to ascertain if there were any other marine 

 organisms in the lake. The results of this attempt have been to 

 show : — 



I. That to the six genera of quasi-marine gasteropods, the shells 

 of which were known, viz., Typhobia, Nassopsis, Limnotrochus, Syrno- 

 lopsis, the so-called Lithoglyphus, and Paramelania, there are now 

 to be added at least two, entirely new generic forms, for which I 

 propose the names* Bathanalia and Bythoceras (figs. 1 and 2). We 

 have therefore now representing the quasi-marine molluscs of Tan- 

 ganyika eight genera of gasteropods, and to these should probably 

 be added among the Lamellibranchiata the so-called TJnio Burtoni 

 and one of the Tanganyika Spathas.f 



* Diagnoses of these new genera will be found in papers now in the hands of the 

 Editor of the 1 Quart. Journ. Micr. Sci.' 



f Complete accounts of the anatomy of all these Halolimnic genera will shortly 

 appear in the c Quart. Journ. Micr. Sci.' 



