xx INTRODUCTION. 



bonis (Characinidse), Siluranodon and Andersonia (Siluridae) are at present only known 

 from the Nile, while Platytamiodus (Cichlidse) is peculiar to Lake Victoria. Mochocus 

 (Siluridae) would also be characteristic of the Nile but for its discovery in Lake Rudolf. 

 Genera distributed from the Nile to the Atlantic coast, but absent from the Congo and 

 the Zambesi, are Hyper opisus and Gymnarchus (Mormyridse), Heteroiis (Osteoglossidee), 

 and Clarotes (Siluridae). Among the genera represented in the great lakes and their 

 neighbouring rivers, but not in the Nile, must be mentioned Varicorhinus and Nemachilus 

 (Cyprinidae) in Lake Tsana, Nedbola (Cyprinidse), Fundulus (Cyprinodontidae), 

 Paratilapia and Pelmatochromis (Cichlidae), and Mastacembelus (Mastacembelidse) in 

 Lake Victoria, and Petrochromis (Cichlidae) in Lake Albert. Nemachilus is interesting 

 as the only African representative of the Loaches, otherwise confined to the Palaearctic 

 and Indian Regions. Varicorhinus has its nearest allies in South-western Asia, 

 Morocco, Lake Tanganyika, and Angola ; Neobola is represented in East Africa and 

 Lake Tanganyika, Petrochromis in Lakes Tanganyika and Nyassa, whilst the four other 

 genera are widely distributed in Tropical Africa. 



A full discussion of the various problems involved in the study of the distribution of 

 the freshwater fishes of Africa will be found in my address to the Section of Zoology 

 at the South African Meeting of the British Association in 1905 (Rep. Brit. Assoc. 

 1905, pp. 412-432). 



MR. LOAT'S REPORT ON THE NILE FISH SURVEY. 



At the beginning of the year 1899 I was asked by the Egyptian Government to 

 undertake a scientific survey and make a collection of the Fishes of the Nile. 



The final arrangements having been made, I left this country for Egypt and arrived 

 at Cairo on the 1st of March. While abroad I was attached to the Medical School, 

 Cairo, which is under the Ministry of Public Instruction. I started work at Cairo 

 soon after my arrival, in order to get some insight into the methods of fishing, the 

 class of men with whom I should chiefly have to deal, and a knowledge of the 

 commoner types of fish, before proceeding further afield. I made frequent visits to 

 the fish-markets, or " Halagers," where the fish are sold by auction, of which there 

 are two in Cairo, one at Boulak and the other in old Cairo, the former being the more 

 important. The halagers are owned by men called " Muitazzims," who rent a certain 

 district from the Government, to which a number of fishermen are attached; these 

 register their names at the halager, a small registration-fee sometimes being charged 

 by the Multazzim, giving them the right to fish in a certain district on the understanding 

 that all fish that are caught must be sold by them at the halager to which they are 

 attached. The sum realized by the catch is generally divided in the proportion of 

 one-third to the Multazzim and the remainder to the fishermen. 



