6 MR. G. A. BOULENGER ON A COLLECTION 
IV. Lake Rudolf}. 
CicHuip2. CHARACINID. 
. Tilapia nilotica Cuv. 
2. a tristrami Gthr. 
— 
6. Citharinus geoffroyi Cuy. 
7. Alestes rueppelliit Gthr. 
SILURIDZ. 8. Distichodus rudolphi Gthy. 
3. Synodontis schal Bl. Schu. 
_ 4 Be smithii Gthr. Pouyprerips. 
Cyprinipa. 9. Polypterus senegalus Cuv. 
5. Barbus, sp. 
The fishes of Lake Nyassa are, with two exceptions, specifically distinct from those 
of the Nile, as pointed out by Dr. Giinther ’, while seven out of forty-three species 
represented in Lake Tanganyika occur both in the Nile and in the rivers flowing into 
the Atlantic. And as the Mormyride, which furnish the two species common to 
Nyassa and the Nile*, have not yet been recorded from Tanganyika, while, with the 
exception of a small stream-Siluroid, not one of the species described from the former 
lake has been rediscovered in the latter, it follows that, although similar in general 
character, the fish-fauna of the two lakes shows no trace of community so far as 
specific forms are concerned, as might have been expected from the absence of direct 
communication between them. 
Before concluding these prefatory remarks, I wish to express my thanks to 
Messrs. J. H. Gardiner and J. Green for their kind assistance in supplying me with 
sciagraphs of the new fishes, which, supplementing the skeletons prepared by 
Mr. Groenvold, have enabled me to add some notes on the osteological characters of 
the genera described as new. 
SERRANID. 
1. LaTES MICROLEPIS, sp. n. (Plate I. fig. 1.) 
Body elongate, its depth 53 times in the total length. Length of head 3 times in 
total length; upper profile nearly straight ; diameter of eye equal to length of snout, 
3$ times in length of head ; lower jaw projecting ; maxillary extending to below centre 
of eye, the width of its distal extremity not quite half diameter of eye; pre- and 
suborbitals finely serrated; cheeks, opercles, and occiput covered with small scales ; 
preopercular border forming nearly a right angle, finely toothed on its vertical limb, 
with two or three widely-separated spines on its lower limb, and with one or two very 
1 Giinther, P. Z. 8. 1896, p. 217. 2 «Study of Fishes,’ p. 230. 
5 Tf, as seems probable, the distinction between Mormyrops zambanenje and M. anyuilloides should not be 
maintained. On the other hand, the Nilotic specimens referred to Mormyrus discorhynchus may prove to 
be specifically separable, Lake Tanganyika might thus ultimately possess no species of fish in common with 
the Nile. 
