174^ CLASSIFICATION OP FISHES^ ETC. 



Familt 5. SPIROBRANCHID^. 

 Belly remarkably short ; vent near the pectoral. 



Macropodus. Tail or caudal fin excessively large and forked. 



CoLisA. Ventral with one very long ray ; the others minute 



or obsolete. 



Trkkopus. Dorsal fin very short, central. 

 Cbltsa. Ventral fins of a single long filiform ray. 

 OsphroTTienus. Ventrals of one very long, and several short rays. 

 Polycanthus. Ventral fins moderate and only pointed. 



Helosxoma. Ventral fins rounded, and smaller than the 

 pectorals 

 Helostoma. Mouth very small and retractile j the teeth on the Ups. 



SpiROBRANCHUs. Mouth larger. 



Spirobranchus. With tessellated teeth ; body more lengthened, rather 



round ; operculum not denticulated. 

 Anabus. Margin of the operculum strongly serrated. 



Ophicephalus. Body eel-shaped ; all the fin-rays soft. 



Tribe II. —MICROLEPTES. — Scales small, or none; 

 branchial aperture large. 



Family 1. SCOMBERIDiE. 

 Body oblong, lengthened, smooth ; caudal fin large, forked ; 

 dorsal fins often divided into finlets ; no spines before the 

 anal fin. 



1. Sub- family Scomberin^. — Scales minute, uniform ; 



dorsals wide apart. 



ScosiBER. Body fusiform ; scales uniform, minute ; tail not 

 keeled. 



Auxis. Dorsal fins distant ; the first short. 



2. Sub-family Thynnin^ Scales largest near the head ; 



dorsals approximate. 



Thynnus. Tail with two elevations and a carinated ridge 



between. 



Orcynus. Pectorals very long, falcate, 



Pelamis. Resembling ThjTinus; with the teeth of Cybium. 



Cybium. Elongated ; scales equal ; teeth large, compressed. 



Thyrsites. Lower jaw longest ; taU not carinated. 



Gemphylus. Body very long ; ventrals minute ; lateral line with 

 large scales. 



Zyphothyca. Body sword-shaped; chin long and pointed; 

 ventrals minute. 



