192 DEEP-SEA FISHES OF THE ATLANTIC BASIN. 



are concerned. Seriola, Oliffoplites, Tr achy not us, and some of the large species of Caranx, 

 such as C. hippos, arc powerful swimuiers, and are likely to make long jourueys, at least 

 as far as from the West Indies to the Bermudas, where many of the species occur casually. 

 Others, like Selene, drift far and wide with the currents, and are found in mid ocean, 

 apparently under much the same conditions as in Nomcus. XomcKS is, however, character- 

 istically a mid-ocean tish, and is not known to breed near the shores, but there is good 

 reason to believe that Selene does. 



Seriola Dunierilii, Risso, is said by Canestrini to occur everywhere in the Mediter- 

 ranean, but to dwell at great dc^pth (« f/rande profondita), so that its capture is uncommon. 

 The young of Seriola are pelagic surface forms. 



Caranx amblyrhynchus, C. «& V. has been found several times under circumstances which 

 would seem to indicate that it came from very great depths, but it so closely resembles in 

 structure the other members of the genus that it is hard to believe that there is not some 

 error of observati(jn. It was brought up by the Blake at station 324 (Lat. 33° 27", Ion. 

 75° 53' 30"), in 047 ftxthoms. 



Porthmeus amia (Lichia amia, Auctorum, in its adult form — Porthmeus argenteus, in young 

 state) is while young a pelagic form, and has been found oil" the west coast of Africa. The 

 young of Chorinemus and of Oligoplites are, according to Hitkeu, also pelagic (Spolia At- 

 lantica, p. 192 (GOO)). Two species belonging to this family have been taken in the deep- 

 sea nets, but it seems hard to believe that they were caught at the bottom. 



Family SCOMBRID^E. 



GU Scomhrin'r, Rafinesque, Indice {Vlttioliogia Siciliana, 1810, 



Scombrini, Bonapaute, Cat. Metodico, 73 (Sub. fam. 228). 



Scombroiclei, Blkeker, Teutameu, 1859, xxii, (Familia 95). 



Scombrida; Gill, Proc. Acad. Nat. Sci. Phila., 1862, 124; Arr. Film. Fishes, 1872, 8 (No. 78).— (Gunther, Cat. 



Fish. Brit. Mus., II, 349-373. — Trichiuridw, in pan, aud Scombridw, in part). — Jordan aud Gilbert, 



Bull, xvi, U. S. Nat. Mus., 1883, 422. 



Physoclystous Acanthopterygians, with body elongate, fusiform; the scales minute or 

 wanting (generally cycloid, but about the thorax larger ones, sometimes ctenoid, are 

 developed, forming the so called corselet of the tunnies). Lateral line distinct, fre(piently 

 sinuous. Head subconic, pointed anteriorly. Mouth rather large, with lateral cleft; upper 

 jaw not protractile; maxillary without supplemental bone; sharp teeth on the jaws and 

 generally on the vomer, sometimes on palatines. Preoperculum entire; operculum well 

 developed, unarmed; in the extremely young the preoperculum is u,sually armed with 

 several radiating spines, subsequently absorbed and lost. Gill-openings large, confluent 

 below. Gill-rakers usually long. Pseudobranchiix; present, large. A slit behind the fourth 

 gill. Brauchiostegals generally 7. Dorsal fln« 2, the flrst composed of rather slender, 

 spinous rays, depressible ui a groove, the second with branched rays, the posterior ones 

 usually detached and separate, forming series of Unlets. The first dorsal is always cither 

 elongate or widely separate from soft dorsal. Anal similar to second dorsal. Caudal 

 peduncle very slender, usually keeled, the caudal deeply forked, adapted for rapid propu I- 

 sion. Ventrals moderate, thoracic. Vertebriie numerous (more than 2.5). Pyloric cicca 

 weU developed, numerous. Stomach sac-shaped. Air bladder frequently absent. 



KEY TO THE GENERA. 



I. Body fusiform, moderately elongate Scomiirin.e, Gill 



A. Spinous dorsal short (of less tlian 12 spines), with wide space separating it from second dorsal ; pec- 

 torals hifj;h up; caudal not carinatcd. 



1. Vomer aud palatines with teeth ; corselet obsolete Scomber 



2. Vomer and palatines toothless; corselet well develo"l)ed Auxis 



B. Spinous dorsal long (of more than t velvo spines), contiguous to the second; jiectorals low; caudal 

 with keels ; pyloric cjeca very numerous Orycnin.e, Gill 



1. Corselet imperfect or obsolete; teeth of jaws strong. 



fl. M to 18 rays in spinous dorsal Scombkromorus 



b. 25 rays in spinous dorsal; jaws beak-like Acanthocybium 



