536 FISHES. 



ACARA. — Body compressed, oblong, covered with ctenoid 

 scales of moderate size. Dorsal spines numerous, anal spines 

 three or four ; base of the soft dorsal nearly uncovered by 

 scales. Teeth in a band, small, conical. Anterior prominences 

 of the first branchial arch very short tubercles. 



Some twenty species are known from the fresh waters of 

 Tropical America, A. bimaculaia being one of the most com- 

 mon fishes of that region. All are very small. 



Herds. — Differing from Acara in having more than four 

 anal spines. 



Some fifty species are known from the fresh waters of 

 Tropical America, especially Central America, where almost 

 every large lake or river is tenanted by one or more peculiar 



Fig. 245. — Seros salvini, from Central America. 



species. They are of rather small size, rarely exceeding a 

 length of twelve inches. 



Genera allied to Heros, and likewise from Tropical 

 America, are Neetroplus, Mesonauta, Petenia, Uaru, and Hygro- 

 gonus. 



CiCHLA. — Form of the body perch-like. Scales small ; the 

 spinous and soft portions of the dorsal fin of nearly equal extent, 

 and separated by a notch ; anal spines three. Each jaw with 

 a broad band of villiform teeth. The outer branchial arch with 

 lanceolate crenulated prominences along its concave side. Dorsal 

 and anal fins scaly. 



Four species from Brazil, Guyana, and Peru. 



