75. CARANGIDiE — TRACHURUS. 431 



bebiud tbe last. Gill- rakers usually long. Brancbiostegals commonly 

 7. Air-bladder present, often bifurcate behind. Pseudobrancliite large, 

 present in all our genera, sometimes disappearing with age. Oesopha- 

 gus unarmed. Pyloric coeca generally numerous. Vertebroe fewer than 

 in the Scombridcv, about 2a in number. Coloration generally metallic 

 and silvery. Genera 25; species about 180, abounding in warm seas, 

 often moving northward in summer, like the Scombridw. JMost of the 

 species are widely distributed, and nearly all are valued as food. 



{Caraiigklx pt. Giiiither ii, 417-485, exclusive of certain genera.) 



* Lateral line armed with bony keeled plates, at least posteriorly. {Caranginw.) 



a. Armature of lateral lino extending its whole length Tkaciiurus, *219. 



aa. Armature of lateral line on its straight posterior portion only. 



h. Dorsals and anal each with a detached finlet Decapterus, 220. 



hb. Dorsal and anal without finlets. 



c. Spinous dorsal developed Caran^x, 221. 



cc. Spinous dorsal rudimentary or disai)i)earing with age ; scales rudimentary. 



Blepharis, 222. 

 *" Lateral line unarmed. 



d. Premaxillarles protractile, 

 e. Anal fin about equal to the soft dorsal, its base longer than the abdomen; 

 tail not keeled. 

 /. Thoracic region treuchant; body excessively compressed. 



y. Dorsal outline more convex than the ventral outline ; jirofile very steep; 

 head very short and high; preorbital very deej). {Sclcninw.) 



Selene, 223. 

 gg. Dorsal outline less convex than ventral ; j)rofile not steep ; preorbital 



moderate. ( CMoroscomhrina: ) Chloro8COMBRUS, 224. 



ff. Thoracic region not trenchant; body moderately compressed. {Tra- 

 chjinotinw.) 



h. Forehead convex .Trachynotus, 22.'>. 



ee. Anal fin much shorter than the soft dorsal, its base not longer than the 

 abdomen; tail keeled. {Scriolhuv.), 

 i. Finlets none. 



j. Dorsal spines free, in adult Naucrates, 226. 



jj. Dorsal spines connected by membrane Seriola, 227. 



tj. A two-rayed (inlcit behind dorsal and anal Elaoatis, 22H. 



dd. Premaxillarles not protractile ; dorsal and anal with finlets; maxillary 

 very narrow, without distinct supplemental bone. {Scomhroi- 

 dinCB.) SCOMBROIDES, 229. 



219.— TRACHURUS Rafiuesque. 

 iSaurels. 



(Rafinesque, Indiced'Ittiologia Siciliana 1810, 20 : type Scomber irachuriis L. = Track urus 

 saurus Raf.) 



Body rather elongate, somewhat compressed, not elevated, tapering 

 to a slender caudal peduncle, which is as broad as deep. Scales i^resent, 

 not very small. Lateral line armed throughout with plates, those on the 

 caudal peduncle larger and spinous; an accessory dorsal branch to the 

 lateral line. Snout rather long. Mouth moderate. Minute teeth mostly 



