OF PISHES mOM LAKE TANGANYIKA. 27 



of this description, and although they are numerically abundant, they belong to half 

 d dozen species at the most. 



Nearly all the new forms which I obtained were killed by dynamite from the 

 tiraggy ledges of the west coast of the lake, where the water was deep enough, about 

 20--35 feet, but not too deep for my men to dive and procure the greater number of the 

 fishes, which, after every shot, were invariably found on the bottom. The numbet 

 of fishes in such situations is really surprising, and on several occasions, after firing^a 

 single cartridge, I obtained more than two tall negroes could well carry, when slung 

 in a bag between them on a pole. 



Only one fish was obtained from anything approaching to the deeper water of 

 Tanganyika, about 400 feet, which was accidentally entangled in a basket dredge, 

 and this was the specimen of the new species Bathyhates ferox described on p. 15. 



Of the fishes which exist on the great mud-plains, which are to be found about 

 1000 feet below the surface in many portions of the lake, or of those which may occur 

 in the vastly deeper portions, absolutely nothing is known. 



The fishes which have been collected, moreover, were obtained almost exclusively 

 from the south-western extremity of Tanganyika, and to suppose that the fishes which 

 occur in this locality are in any way representative of the fishes, even in similar 

 situations, throughout the whole lake, would be as absurd as if we were to suppose 

 that the shoal-water fish of the whole English Channel could be obtained from a few 

 miles of rocky beach about the Needles and the Isle of Wight. That the fishes diff^er 

 ill different portions of the lake I have myself observed, and it has also been shown 

 in a most striking manner by the fact that of the six species previously described 

 from Tanganyika, which were collected by Captain Hore near Ujiji, I have only re- 

 discovered one. 



The fishes which have been already obtained in Tanganyika, or in Nyassa for that 

 matter, must therefore be regarded as merely the surface skimmings of these lakes, 

 and as in no sense representing the whole fish-fauna they may contain. 



Eeally deep water, 300 fathoms and upwards, is to be found over large areas in 

 Nyassa, and to what depth the water in Tanganyika may reach no one knows ; but 

 it is obvious that where water of such depth exists, if the lakes in which it is con- 

 tained have been permanent for any great length of time, there ought to be modified 

 forms of the freshwater fishes to suit such depths, and, with the exce^^tionoi Bathyhates 

 ferox, these have not yet been obtained. 



In the case of Tanganyika, the interest which attaches to the future exploration of 

 its deeper water is particularly great, since I have elsewhere shown that the majority 

 of the Halolimnic animals, most of the molluscs, sponges, and so forth, are exclusively 

 deep-water forms. In fact, it was only when my dredging capacities, so to speak, 

 were giving out, that the more interesting of these forms, the genera Typhohia^ 

 Bathanalia, and the like, were beginning to come in. 



