100 CLASS XIV. 



Alestes MUELL., VALENC. Abdomen rotundate. Scales large. 



Sp. Myletes Hasselquisti Cuv., Cyprinus Dentex L. (and Salmo niloticus 

 ejusd.), Cuv. Mem. du Mus. iv. PI. 21, fig. 2, R. Ani., ed. ill., Poiss. 

 PL 103, fig. i, Myletes Baramoze JOANNIS, GUERIN Magas. de Zool. 1835, 

 Cl. IV. PI. 6 ; in the Nile, where it is named by the Arabs Raji; the scales 

 fall off very readily ; the caudal fin is large and deeply forked. This fish 

 attains a length of i' to 15". 



Myletes Cuv. (in part), MUELL. Abdomen carinate, serrate. 

 Scales small. 



Sp. Myletes macropomus Cuv., Mem. du Mus.v. PL 21, fig. 8, &c. All these 

 species are from S. America. 

 Tometes VALENC. 

 Myleus MUELL. 



Serrasalmus Cuv., LAC. Teeth in both jaws mostly in a single 

 row, triangular, trenchant. Body compressed, with belly serrate. 

 Scales small. Branchiostegous membrane with four rays. 



a) Palatine teeth none. 



Sub-genera: Pygocentrus, Pygopristis, Catoprion MUELL. 



Sp. Serrasalmus Piraya Cuv., Mem. du Mus. v. PI. 28, fig. 4, Piraya or 

 Piranha MARCGR. Hist. not. Bras. p. 165 ; this and another species, Pygo- 

 centrus niger MUELL., swim together in large troops in the rivers of Brazil 

 and Guyana ; they are very voracious and so bold that they attack even 

 large animals that chance to get into their shoal, and in a short time con- 

 sume them to the bone. An ox cannot reach the far side of a stream only 

 thirty or forty feet wide without nearly dying, and in part gnawed to a skele- 

 ton. The Guaraunos, who preserve their dead as skeletons, hang, according 

 to GUMILLA, the bodies in the stream for a night, and on the following day 

 have a clean-made skeleton 1 . 



b) Palatine teeth triangular, acute, in a single row. 



Serrascdmo MUELL. 



Sp. Serrasalmus rhomleus LACEP., Salmo rhombeus L., PALL. Spicil. Zool. 

 vni. PL 5. fig. 3, BLOCH Ichth. Tab. 383. Guiana, Surinam, &c. 



of mouth large, produced beyond the eye. Abdomen not 

 serrate. Hydrocyon Cuv. 



1 SPIX Pise. Brasil, Fasc. I. From such stories deductions may be made, and still 

 much that is remarkable remains. See also the accounts respecting these gluttonous 

 fishes by AUGUSTE DE SAINT-HILAIRE and SCHOMBURGK in CUVIER and VALENCIENNES 

 Hist. not. des Poissons, xxn. pp. 290, 291, 293, 294. 



