SYNODONTIS. 385 



The specimen figured in the c Description de l'Egypte,' which is not to be found in 

 the Paris Museum, came no doubt from the Lower Nile, where the species has not 

 been obtained since. Our specimens are from the White Nile. The species is also 

 known from Lake Chad, the Senegal, and the Niger. 



List of specimens examined : — 



3 Khartum. — Petherick, 1861. (Types of S. guentheri.) 



1 Fashoda.— Loat, 18.4.01. 



7 Mouth of Lake No.— Loat, 25-27.1.01. 



1 Lake Chad.— Capt. Gosling, 1905. 



1 St. Louis, Senegal.— Delhez, 1899. 



1 Lokoja, N. Nigeria.— Budgett, 1903. 



3 Abo, S. Nigeria. — Dr. Ansorge, 1901. 



1 Assay, S. Nigeria. — Dr. Ansorge, 1901. 



1 Niger Delta.— Dr. Crosse, 1895. 



Marno, who has sent a large number of specimens to the Vienna Museum, has 

 noted that he has never seen this fish swimming otherwise than upside down *. 



This species stands quite apart from the other members of the genus, and the fact 

 that it has so often been confounded with S. batensoda can only be accounted for by 

 the rarity of specimens in collections. Thus Valenciennes had only a specimen of 

 S. batensoda before him when he prepared his account of the Silurida^, whilst Gunther 

 was only acquainted with the true S. membranaceus. Vaillant correctly distinguished 

 the two, but he regarded the example of the former species in the Paris Museum as 

 the type of S. membranaceus, whilst a reference to Geoffroy's figure clearly shows the 

 latter to be identical with Vaillant' s S. guentheri, 



* See note under S. batensoda, p. 382. 



3d 



