THE TANGANYIKA PROBLEM. 
127 
Passing north from Nyassa, we find that, with the 
exception of the small crater pools occupying extinct cones 
which occur along the continuation of the lake’s valley 
towards Rukwa, there are encountered no fresh waters of 
any dimensions until we reach Kela, a small, nearly circular, 
mere, with practically no fauna at all in it, beyond some 
siluroid fishes and swarms of a minute species of Bithynici. 
Curiously enough, Kela is within 20 miles of Tanganyika, 
and yet there is not a single specific identity between the 
fauna characteristic of the two lakes. Far to the east of 
Kela lies the larger lake Rukwa ; it is a shallow sheet of 
water occupying the floor of a continuation of the Nyassa 
valley. Our most definite information respecting this lake 
is that obtained by Mr. Wallace,* who, in 1897, made an 
extensive geographical examination of the region, but who 
observed nothing but minute shells, probably those of 
Bithynici , and a number of siluroid fishes. f Far to the 
west, again, we have the shallow and extensive expanse of 
water which constitutes Lake Bangweolo. This lake is 
known to contain siluroid fishes, but Mr. Weatherley 
reports that it is “absolutely shell-less.” Somewhat further 
to the north lies Lake Mwero, a deep lake lying in a 
secondary fold similar to that of Lake Rukwa, to the east 
of Tanganyika. It has a much more profuse fauna than 
either Rukwa, Bangweolo, or Kela. Among the fishes 
occurring in Mwero, there have been recorded the following 
fourteen different types : — 
* Journal of the Royal Geographical Society , I S 9 7- 
t I believe some further information respecting the fauna of Lake Rukwa has more 
recently been obtained by Dr. Fiilleborn, but no account of this appears yet to have 
been published. See Chapter IV., p. 73, of present work. 
