382 silueid^:. 



Described by Kuppell from specimens obtained at Cairo, where they descend in 

 small numbers during the flood-time, this species has often been confounded with the 

 following, from which it differs in several very important characters. It has not been 

 rediscovered in the Lower Nile since the clays of Geoffroy and Ruppell ; Mr. Loat's 

 specimens are from the White Nile and the Bahr-el-Gebel. It also occurs in the Chad 

 Basin, in the Senegal, and in the Gambia. 



List of specimens examined : — 



3 South of Khartum. — Capt. Flower, 1903. 



39 Fashoda.— Loat, 14-31.3.01. 



17 Mouth of Lake No.— Loat, 31.1-15.2.01. 



1 Gondokoro.— Loat, 27.1.02. 



1 Bahr-el-Gebel.— Drury, 1901. 



1 11. Shari-Wasu at Maidugari. — Capt. Gosling, 1904. 

 3 Kaedi, Senegal.— Delhez, 1899. 



2 McCarthy Id., Gambia.— Budgett, 1900. 



According to Kuppell the fishermen in his clays knew the fish as " Shal baten soda" 

 which means " Schal with a black belly." According to Loat this species and the 

 following are called " Gargour gelarby" or " G darby" {^j j?$) at Omdurman. 

 " Schal gemel" (lU>- Jit) is their name in Lower Egypt according to Geoffroy, whilst 

 in Upper Egypt Rifaud has designated them as " G our gar Chami" 



The curious fact of S. hatensoda and S. membranaceus having the lower parts darker 

 than the upper appears to be connected with their habit of swimming in a reversed 

 position, the belly turned upwards. This habit, known to the ancient Egyptians, who 

 have frequently represented them in that attitude *, has been described by Geoffroy, 

 who says they nearly constantly swim on their back, moving quite freely forwards or 

 sidewards ; but if alarmed they revert to the normal position to escape more rapidly. 

 These observations have been verified by Mr. Loat. 



A third species, of similar coloration, has been discovered by Budgett in Northern 

 Nigeria and described by me as S. resujjinatus^. In its structural characters it is 

 intermediate between S. clarias and S. batensoda. 



* Cf. Lepsius, Denkmaeler, Abth. ii. pi. ix. It is also well represented in the tomb of Ti at Sakkara 

 (unpublished photograph in the collection of Prof. Flinders Petrie). 

 f Proc. Zool. Soc. 1904, i. p. 199, pi. viii. 



