DISTICHODUS. 145 



D. rostratus grows to the same large size as D. niloticus, our largest specimen measuring 

 620 millimetres. 



The habitat extends from the Lower Nile to the Victoria Nile and to the Senegal 

 and Niger. The specimens examined are from the following localities : — 



1 Lower Nile.— Petherick, 1861. (Type.) 



2 Beni Souef.— Loat, 2.10.99. 



2 At a regulator near Luxor. — Loat, 23.10.00. 



1 In a pond near Kosheh, Nubia. — Loat, 13.3.00. 



1 Gondokoro.— Loat, 28.2.02. 



1 Fajao, Victoria Nile.— Budgett, 25.4.02. 



1 Lake Chad.— Capt. Gosling, 1904. 



1 West Africa. (Type.) 



1 St. Louis, Senegal. — Delhez, 1899. 



1 Niger.— W. A. Forbes, 1883. 



1 Jebba, Upper Niger. — Capt. G. F. Abadie, 1898. 



1 Mureji, Upper Niger.— Budgett, 1903. 



2 Abo, Lower Niger. — Dr. Ansorge, 1902. 

 10 Agberi, Lower Niger. — Dr. Ansorge, 1902. 



1 R. Benue, north of Ibi. — Norton Smith, 1906. 



In Egypt the fish is confonncled with D. niloticus by the native fishermen. The 

 older authors have also failed to discriminate between the two species, and it is now 

 impossible, from the imperfect definitions given, to decide to which the names niloticus, 

 cegyptiacus, and nefasch should be applied. The figure given in the ' Description de 

 l'Egypte 'refers, however, to the present species, whilst Geoffroy's description was based 

 in part on the preceding *. As Gunther was the first to make the distinction, I have felt 

 bound to use the names as applied by him, although I should myself have preferred to 

 retain the name niloticus or nefasch for the form with larger scales, figured by Geoffroy, 

 instead of the other. 



* Dr. Pellegrin kindly informs me that the Nile examples from Greoffroy St.-Hilaire's collection (1799), 

 which the Paris Museum still possesses, belong to the latter, having D. 24, A. 24, Sq. 94-102 -^r, whilst 

 an example from the Nile from Olivier's collection (1795) is referable to D. rostratus, having larger 

 scales (92 ^). That the scales are accurately represented in the figure accompanying Geoffroy's description 

 is shown by a comparison with the figure of Serrasalmus citharus on the same plate. 



