xxi OSTARIOPHYSI 575 



Mouth usually more or less protractile, toothless ; lower pharyngeal bones 

 large, falciform ; body naked or scaly ; no adipose dorsal fin 



3. Cyprinidae. 

 II. Parietal bones usually fused with the supraoccipital ; symplectic 



absent ; body naked or with bony scutes ; mouth usually toothed, with 

 barbels ; adipose fin often present. 



Ribs attached to strong parapophyses ; operculum well developed 



4. Siluridae. 

 Ribs sessile ; parapophyses absent ; operculum more or less developed ; 



mouth inferior ....... 5. Loricariidae. 



Ribs sessile ; strong parapophyses to the vertebrae ; operculum absent 



6. Aspredinidae. 



Fam. 1. Characinidae. Mouth non-protractile, usually 

 bordered by the praemaxillaries and the maxillaries, rarely by 

 the praemaxillaries only ; jaws usually toothed. Parietal bones 

 united in a sagittal suture or separated by a fontanelle : opercular 

 bones well developed ; symplectic present. Pharyngeal bones 

 normal, with small teeth. Eibs mostly sessile ; no parapophyses 

 in the thoracic region ; epipleurals and epineurals, mostly free 

 floating. Pectoral fins inserted very low down, folding like the 

 ventrals. Body covered with scales. An adipose dorsal fin 

 often present. 



This is a very generalised type, although perhaps not directly 

 derived from the bony Ganoids, as believed by Sagemehl. The 

 species number about 500, and are confined to the fresh waters 

 of Africa and Central and South America. The classification of 

 the family is still in an unsatisfactory state, but the division into 

 the following groups (hardly deserving the rank of sub-families), 

 although quite provisional, appears preferable to the highly arti- 

 ficial arrangement hitherto adopted : 



I. No adipose fin. 



A. ERYTHRININAE. Carnivorous ; teeth strong ; maxillary large ; gill- 



openings wide ; scales cycloid. American : Macrodon, Erythrinus, 

 Lebiasina, Pyrrhulina, Corynopoma. 



II. Adipose fin usually present. 



B. HYDROCYONINAE. Entirely or partially carnivorous ; teeth strong ; 



maxillary well developed ; scales cycloid ; lateral line usually nearer 

 ventral than dorsal outline (sometimes only on the tail). African : 

 Sarcodaces, Hydrocyon, Bryconaethiops, Alestes, Micralestes, Peter sius, 

 American : Acestrorhynchus, Boulengerella, Acestrorhamphus, Crenu- 

 chus, Chalceus, Brycon, Bryconops, Bryconodon, Creagrutus, Chalcinus, 

 Brachychalcinus, Pseudocorynopoma, Stichonodon, Gastropelecus, Tetra- 

 gonopterus, Scissor, Chirodon, Piabucina, Iguanodectes, Aphiocharax, 

 Salminus, Oligosarcus, Agoniates, Paragoniates, Leptagoniates, Anacyrtus. 



