26 ME. G. A. BOULENGEE ON A COLLECTION 



deep. Scales 42 in a longitudinal line, 11 in a transverse line. Silvery, with a darker 

 lateral stripe ; dorsal and anal with greyish horizontal streaks. 



Total length 80 millim. 



A single specimen from Mbity Rocks. 



POLTPTERID^. 



35. PoLYPTKRUS BicHiR Geoflfr. (1). 



Mr. Moore informs me that a Polypterus occurs in moderate abundance in the lake, 

 and although he did not bring home specimens, he feels tolerably confident, from his 

 recollection of them, that the fish belongs to the typical P. bichir, which occurs in 

 the Nile, the Niger, and the Congo, and not to any of the closely-allied species that are 

 often confounded with it. 



APPENDIX. By J. E. S. Moore. 



In the foregoing descrijition of the fishes which I succeeded in bringing through 

 from Tanganyika to the coast, Mr. Boulenger has already alluded to the difficulties 

 that were experienced in transporting them in spirit, through several hundred miles 

 of often trackless, always scorching, forest, and of the inevitable losses which this 

 entailed. The difiiculties of transport, however, were by no means all. It must be 

 nearly impossible for anyone who has not visited the African lakes to realize their 

 huge size and oceanic character. 



One must be as heavily equipped for dredging in these waters as would be required 

 for efi"ective operations in the open sea. It will easily be understood, therefore, how 

 incomplete our knowledge of the deep-water fauna of these lakes must be considered, 

 when it is remembered that on Tanganyika I was of necessity forced to work with 

 native dug-out boats, and with nothing better than the natives themselves as motive 

 power. 



In the case of the fishes, moreover, there are no sources of collateral evidence from 

 which we may obtain any insight into the nature of the deep-water forms, for dead 

 fishes, unlike molluscs, leave no shells behind them, to be thrown upon the beaches of 

 the lake, whereby, in the case of the molluscs, we gain some knowledge of the 

 existence of forms which have not been seen alive ; nor can we make use of the 

 knowledge of the inhabitants in this matter, for the best of the Tanganyika natives 

 are but wretched fishermen, merely using either surface traps, or light and inefficient 

 drag-nets, which are thrown out a short distance from the shore and then hauled in 

 to the land. Such nets are necessarily used only on smooth sandy beaches, and 

 consequently the fishes caught in them are only of those Sj^ecies which inhabit places 



