PISCES. 85 



Sp. Synodont'is macrodon Isid. Geoffe. Saint-Hilaike, Silurus Clarias 

 Hasselquist ; — Synod, arabi Valenc, Silurus schal Bloch, Syst. Ichth., 

 SoNNiNi Voyage en Eyypte, PI. cr, fig. 2 ; — Synod, serratus Rueppell, 

 Beschr. und Ahhild. 7ieutr FischeimNil entdecM, 4to. 1829, Tab. 11. — Synod, 

 maciilosus Rueppell, ibid. Tab. iii. fig. i . 

 All the known species are found in the Nile. 



Pimelodiis Valenc. (species of Pimelodus Lacep.). Body 

 naked. Teeth in maxillse veiy thin, crowded, sometimes none; 

 palate edentulous. Branchiostegous membrane mostly with eight 

 rays (5 — 12). Dorsal fins two, the second adipose, frequently small, 

 placed above tlie anal. Cirri six or eight. 



Sp. Pimelodus Sebce Cuv., Silurus clarias L., excl. synon., Seba Thesaur. in. 

 Tab. 29, fig. I ; Pimelodus catus Cuv., Silurus catus L., Cuv. et Valenc. 

 Poiss. XV. PI. 432, &c. 



The species of this genus are very numerous in warm regions, especially 

 in the western hemisphere. 



Calophysus Muell. and Trosch.' 



Hypophthahnus Spix (in part), Yalenc. Teeth none. Eye.s 

 placed at the inferior margin of jaw. Branchiostegous membrane 

 with foxu'teen or fifteen rays. 



Sp. Hypophthahnus marginatits Valenc, Cuv. et Valenc. Hist, nat, des 

 Poiss. XV. PI. 439 ; — Hypophth. Spixii Val., Hypophthalmus edentatus 

 Spix, &c. 



Ageneiosus Lacep., Valenc. 



Ketengus Bleeker. Genus unknown to me, with four cini^ 



Arges Valenc. Teeth bifid at the apex. Branchiostegous mem- 

 bi'ane with four rays. Eyes small. Cirri two. 



Sp. Arges Sabalo Val., Hist. nat. des Poiss. PI. 444, Peru. 



To this genus Valenciennes refers the small species of fish which Hum- 

 boldt has described under the name of Pimelodus cydopum, and which 

 lives in brooks in the high ranges of Quito. It resides also in subterranean 

 lakes, which appear to communicate with the volcanos of these regions, at 

 least if, as the natives assert, it is the same species which is ejected with 

 mud from the Cotopaxi sometimes by thousands. Humb. Recueil d'Obser- 

 vations de Zoologie et d'Anat. compar. i. pp. 21 — 25, PI, 7. 



1 Compare Mueller and Troschel Horce Ichthyologicm, 3, 1849, PP- ^> ^• 

 '■^ P. Bleekek, Nieuioe Bijdrage tot de Kennis der Slluroieden von Java. Batavia, 

 5, p. 9. 



