192 DEEP-SEA FISHES OF THE ATLANTIC BASIN. 



arc concerned. Seriola, (>li<)oplife.i, Trachynotus, and some of the large species of Caranx, 

 such as C. hippos^ arc powerful swimuiers, and are likely to make long journeys, 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, 

 api)arently under much the same conditions as in Nomeus. Nomeus is, however, character- 

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

 reason to believe that Selene does. 



Seriola Dumerilii, Eisso, is said by Canestrini to occur everywhere in the Mediter- 

 ranean, but to dwell at great depth (a grands prof ondita), so that its cajiture is uncommon. 

 The young of Seriola are pelagic surface forms. 



Garanx amblyrhynvhus, G. & 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 observation. It was brought up by the Blake at station 324 (Lat. '33° 27", Ion. 

 75° 53' 30"), in 647 fathoms. 



PorthmeuH amia(Lichia amla, Auctorum, in its adult form — Porthmcus arf/enteiis, in young 

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

 yonng of Chorlnemus and of OHgoplltes are, according to Liitkeu, also pelagic (Spolia At- 

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

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



Family SCOMBRID^E. 



Gli Scomhrini, Rafinesque, Indice d' Ittioliogia Siciliana, 1810, 



Scomhrhii, Bonaparte, Cat. Metodico, 73 (Sub. fam. 228). 



Scomhrohlei, Bleeker, Teutamen, 1859, xxii, (Familia 95). 



Scomhridw, Gill, Proc. Acad. Nat. Sci. Phila., 1862, 124; Arr. Fam. Fishes, 1872, 8 (No. 78).— (GuNTHER, Cat. 



Fish. Brit. Mus., li, 349-373. — Tiichiuridw, in part, aud Scombridix, in part). — Jordan and 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, frequently 

 sinuous. Head subcouic, 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 usually armed with 

 several radiating si)ines, subsequently absorbed and lost. Gill-openings large, continent 

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

 gill. Branchiostegals generally 7. Dorsal fins 2, the first composed of rather slender, 

 spinous rays, depressible in a groove, the second with branched rays, the posterior on<;s 

 usually detached and separate, forming series of flnlets. The first dorsal is always either 

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

 peduncle very slender, usually keeled, the caudal deeply forked, adapted fin- rapid pi'opul- 

 sion. Ventrals moderate, thoracic. Vertebra numerous (more than 25). Pyloric cieca 

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



KEY TO THE GENERA. 



I. Body Aisiforni, moderately elongate Scombrin.15, Gill 



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

 torals high up ; caudal not carinated. 



1. Vomer aud palatines with teeth ; corselet obsolete .Scomber 



2. Vomer and p.alatinos toothless ; corselet well developed Auxis 



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

 with keels ; pyloric Cicca very numerous Ok vcnin.e, Gill 



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



a. 11 to 18 rays in siiiiious dorsal Scombekomorus 



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



