OSTARIOrHYSI. 217 



it may be very small. When well developed it has a pneumatic 

 duct. Pectoral arch suspended from the skull, mesocoracoid 

 present. The great majority of freshwater fishes are included 

 in this sub-order. 



Fam. 16. Characinidae. Body scaly, head naked ; barbels absent, 

 margin of upper jaw usually formed by the premaxillaries and maxillaries, 

 rarely by the premaxillaries only ; jaws usually toothed ; parietals 

 distinct from supraoccipital ; symplectic present ; generally a small 

 adipose fin behind the dorsal ; pelvics abdominal ; pyloric appendages 

 more or less nvunerous ; air-bladder divided into two portions ; pseudo- 

 branch absent or inuch reduced. Freshwaters of Africa and of tropical 

 America. In America they replace the Cyprinoids ; unknown as fossils. 



Erythrinina, Adipose fin absent ; trop. Amer. The genera 

 are Macrodon, Erythrinus, Lehiasina, Nannostomus, Pyrrhulina, 

 Corynopoma. 



Curimatina. A short dorsal and an adipose fin ; dentition im- 

 perfect ; trop. Amer. ; Prockilodus, Caenotropus, Hemiodus, 

 Saccodon, Parodon. 



Citharinina. A ratlier long dorsal and an adipose fin ; minute 

 labial teeth ; trop. Afr. Citharinus Cuv., attaining to 3 ft. 



Anastomatina. Short dorsal and an adipose fin ; teeth in both 

 jaws well developed ; the gill membranes grown to the isthmus ; 

 nasal openings remote from each other ; trop. Amer. Lepo- 

 rinus, Anastomus, Rhytiodus. 



Nannocharacina. Like the last, except that incisors are notched, and 

 nostrils close together. Nannocharax. 



Tetragonopterina. Short dorsal and an adipose fin ; teeth well 

 developed, notched or denticulated ; gill-membranes free from the 

 isthmus ; nasal openings close together ; S. Amer. and trop. 

 Afr. Alestes M. and T., trop. Afr. ; Tetragonopterus Cuv., 

 trop. Amer. Of the other genera Nannaethiops and Bryconae- 

 thiops are African, the rest are S. American, viz., Chirodon, 

 Megalobrycon, Gastropelecus, Piabucina, Scissor, Pseudochalceus, 

 Aphyocharax, Chalceus, Brycon, Chalcinopsis, Bryconops, Creagrutus, 

 Chalciniis, Piabuca, Paragoniates, Agoniates. 



Hydrocyonina. Short dorsal and adipose fin ; teeth well developed 

 and conical ; gill-membranes free from the isthmus ; nasal openings 

 close together. S. Amer. and trop. Afr. Fishes of prej^ 

 Hydrocyon Cuv., trop. Afr., and Cynodon Spix., S. Amer., 

 both to 4 ft. Except Sarcodaces from W. Afr. the other genera 

 are trop. Amer., e.g., Anacyrtus, Hystricodon, Salminus, Oligo- 

 sarcus, Xiphorhamphus, Xiphostoma, etc. 



Distichodontina. Dorsal fin rather elongate, adipose fin present ; 

 gill-membranes attached to the isthmus ; belly rounded. Trop. 

 Afr. Distichodus M. and T. 



Ichthyborina. An adipose fin ; dorsal rays 12 to 17 ; gill-mem- 

 branes free from the isthmus ; belly rounded ; canine teeth ; trop. 

 Afr. Ichthyborus Giinth., Nile ; Eugnathichthys, Phago, W. Afr. 



Crenuchina. Dorsal fin rather elongate, an adipose fin ; gill- 

 membranes free from the isthmus ; belly rounded ; without canine 

 teeth. Crenuchus Giinth., Brit. Guiana ; Xenoclmrax, W. Afr. 



