162 



CYPEIOTD^. 



The Labeos include some of the largest Cyprinids, individuals of one of the Congo 

 species attaining a length of over three feet. 



The snout, and sometimes also the regions above and below the eyes, bears, at 

 least in the breeding-season, horny tubercles on a tumefied fleshy base, which vary 

 much according to the species and also according to the individuals. They are 

 present in both sexes, but more developed in the males, and as they drop off 

 immediately after the nuptial period, only their crater-like bases are seen in most 

 specimens in collections. These horny tubercles are simply knob-like in L. niloticus, 

 horie, and coubie, whilst in L, forskalii and its near allies each tubercle is crowned by 

 a circle of spinules. 



Over sixty species of this genus are known, from Southern Asia and Africa. The 

 African species, of which I have given a synopsis in the ' Annals and Magazine of 

 Natural History,' (7) xii. 1903, p. 355, number thirty. Of these, according to our present 

 knowledge of their distribution, eleven are peculiar to the Congo system, seven to 

 East Africa east of the Nile system, southwards to the Zambesi (including Lake 

 Nyassa), four to the Nile, four to South Africa (Orange and Limpopo Eivers), two to 

 West Africa from the Niger northwards, one to the Cameroon district, and one 

 species is common to the Nile system and to the Senegal-Niger. 



Synopsis of the Species. 



I. Inner surface of lips not bearing transverse plicae in addition to the sharp ridges ; eyes perfectly 



lateral, visible from above and from below ; snout hardly as long as or shorter than post- 

 ocular part of head. 

 Upper lip bordered with rounded or subcorneal papillae ; dorsal fin with 



14 to 17 branched rays, its upper edge usually concave, rarely 



straight or slightly convex ; scales 41-45 R /~ in i , 5 or 6 between 



lateral line and root of ventral . . . . 1. L. niloticus, Forsk. 



Upper lip bordered with conical papillae forming a very distinct fringe ; 

 dorsal fin with 12 to 14 branched rays, its upper edge straight or 

 more or less convex in the adult ; scales 40-44 sK^:, 4 or 5 between 

 lateral line and root of ventral 2. L. horie, Heck. 



II. Inner surface of lips bearing transverse plicae formed by series of papillae ; snout at least as 



long as postocular part of head in the adult. 

 A. Eyes perfectly lateral, visible from above and from below, or nearly perfectly lateral. 

 Dorsal fin with 11 to 14 branched rays, its upper edge straight or more 

 or less convex in the adult ; snout at least as long as postocular part 



6— — 7— 



of head ; scales 36-40 gf^f? 4 to 5^ between lateral line and root 



of ventral ........ 3. L* coubie, lliipp. 



