896 Bulletin ^7, United States JVational Afuseum. 



the occipital keel prominent, usually trenchant. Month of varying size, 

 the dentition various, the teeth generally small ; premaxillaries usually 

 protractile; maxillary with or without a supplemental bone ; preopercle 

 usually entire in the adult, in the very young armed with 3 or more 

 spines. Lateral line complete, anteriorly arched, the posterior part 

 straight, sometimes armed with bony plates. Dorsal fins more or less sep- 

 arated, the spinous part rather weak, the spines usually depressible in a 

 groove; anal fin long, similar to the soft dorsal, always preceded bj' two 

 stiff spines, usually separate, but in the young often more or less connected 

 with the fin or with each other ; these sometimes disappear with old age, 

 and sometimes the spinous dorsal also vanishes ; often a procumbent 

 spine before the dorsal fin; ventral fins thoracic, well developed, I, 5; 

 caudal peduncle very slender, the fin widely forked ; pectoral fins narrow. 

 Gill openings very wide, the membranes usually not united, free from the 

 isthmus. Gills 4, a slit behind the last. Gill rakers usually long. Bran- 

 chiostegals commonly 7. Air bladder present, often bifurcate behind. 

 Pseudobranchiai large, present in all our genera, sometimes disappearing 

 with age. (Esophagus unarmed. Pyloric (loeca generally numerous. 

 Vertebrie fewer than in the <Sco»i&m?c(', usually 10 + 14 = 24 in number. 

 First superior pharyngeal without teeth; second, third, and fourth sepa- 

 rate, with teeth ; lower pharyngeals separate. Coloration generally 

 metallic and silvery or golden. Genera 29 ; species about 200, abounding 

 in warm seas, often moving northward in summer, like the Scomhrida'. 

 They swim swiftly, often with the dorsal fin above the snrface of the 

 water. Most of the species are widely distributed, and nearly all are 

 valued as food. {Carangida', part, Giinther, Cat., 11, 417-485, 1860, exclu- 

 sive of certain genera.) 



ScOMDUOIDIN^i: 



a. Premaxillaries not protractile (except iu the very young); pectoral fins short, rounded; 

 BO ft dorsal similar to anal, both much longer than abdomen; lateral line unarmed. 

 h. Maxillary without supplemental bone; no pterygoid teeth ; scales linear, embedded. 



Oligoplites, 411. 

 aa. Premaxillaries protractile. 



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

 Seriolin* : 

 c. Pectoral fin short, not falcate; maxilU>ry with a distinct supplemental bone. 

 d. Dorsal spines low and weak. 



e. Dorsal and anal.fins without finlets. 



/. Membrane of dorsal spines disappearing with ago. Naucrates, 412. 

 ff. Membrane of dorsil spines persistent. Seriola, 413. 



ec. Dorsal and anal fins each with a detached two-rayea finlet. Ela(1.\tis, 414. 

 hh. Anal fm about as long as soft dorsal, its bas(^ longer than abdomen. 



(J. Maxillary with a supplemental lione; lateral line arched anteriorly, usually armed 

 posteriorly; pectoral long, falcate. 

 Carangin.i;:* 

 h. Dorsal outline more strongly curved than ventral outline. 



i. Dorsal and anal each with a single detached finlet; body slender. 



Decapterus, 41.5. 



* The genera of Oiranrjinpc here recognized are all closely allied to Caranx, and the known 

 species form an almost unbroken series from Dcc((pferns on the one extreme to Sflnte on the 

 other. They might well all be reunited with Canmx as Giinther and others have proposed. 



