BARB IIS. 199 



anal fin in both these species as well as in all the other members of the genus, 

 inhabiting the Nile system. A number of small species, probably confounded by 

 previous collectors with the young of B. perince, have, thanks to Mr. Loat's careful 

 and extensive survey, been added to the fauna of the Nile. 



But it is especially in the new exploration of the head-waters of the Blue Nile that 

 important additions have been made to our knowledge. This knowledge rested 

 exclusively on the descriptions published by Ruppell nearly seventy years ago, only 

 some of the types of these descriptions being preserved, in a stuffed condition, in the 

 Senckenberg Museum at Frankfort-on-the-Main. Not only did Mr. E. Degen, on 

 his visit to Lake Tsana in 1902, succeed in obtaining examples of all the species 

 discovered by Ruppell, but his collection, comprising numerous and carefully selected 

 series of specimens, preserved in spirit, has added to the list several species which were 

 previously unknown. The study of these Fishes, which cluster round B. lynni, has 

 been a bewildering one to me, from the very close affinity connecting them ; and 

 nothing short of the fine series brought together by Mr. Degen could have enabled 

 me to estimate, correctly, as I hope, the value of the characters used for defining 

 the species. Mr. Degen's collection has been usefully supplemented by another 

 made quite recently by Mr. Za/phiro and presented to the British Museum by 

 Mr. W. N. McMillan. 



In the case of several of these allies of B. bynni, it is extremely surprising that 

 Fishes agreeing so closely in the form and scaling of the body and in the position and 

 structure of the fins, in the pharyngeal teeth, and also in the skeleton, so far as I have 

 been able to ascertain, should differ very considerably in the proportions of the various 

 parts of the head, the form and development of the lips, and the relative length of the 

 barbels. I trust that the rich material which I have had the privilege of studying has 

 enabled me, through comparisons of numerous specimens of all sizes, to form a correct 

 estimate of the changes that take place with age, and that the number of species has 

 not been unduly multiplied, although it is, of course, quite possible that some of them 

 are founded on hybrids *. 



Lake Victoria has also, quite recently, yielded several additions to this genus, 

 thanks to the collections made by Col. Delme Radcliffe and by Mr. E. Degen. 



A remarkable fact is the absence of any representative of this genus in the Senegal 

 and the Gambia, as well as in Lake Chad. Only one species (B. nigeriensis, Blgr.) is 

 known from the Niger. More than one-third of the known African species are from 

 the head-waters of the Blue Nile aucl from Africa east of the great lakes. 



* The European Cyprinids, as is well known, have yielded numerous more or Jess well-established 

 examples of hybridism, congeneric and digeneric, originally described as distinct species. 



