FAMILY SCOMBRID.E. 109 



GENUS TRICHIURUS. Linneus, Cuvier. 



A single continuous dorsal Jin. No corselet nor caudal ridge. No ventral nor caudal fins. 

 Body elongated, compressed, ribbon-shaped. Tail ending in a filament. 



THE SILVERY HAIR-TAIL. 



Trichideus lepterus. 

 plate xii. fig. 35. — (state collection.) 



Trichiurus lepturus. LlN. Syst. Nat. 



Silvery Hair-tail, T. argenteus. Mitchill, Lit. and Phil. Tr. Vol. 1, p. 364. 

 Le Tnchiure de VAtlanliaue. Cov. et Val. Hist. Poiss. Vol. 8, p. 237. 

 T. armatus et muticus. Gray, Griff. Cuv. Vol. 10, p. 349, pi. 6. 



Characteristics. Uniform silvery. Head one-seventh of the total length. Lateral line yellow. 

 Length 28 inches. 



Description. Body long, tapering, compressed. Back acute, and abdomen more full and 

 rounded. Tail compressed, tapering very gradually to a fine point, three inches and a half 

 long from the end of the dorsal. A smooth silvery easily detached skin, with no vestige of a 

 scale apparent under the magnifier. Lateral line distinct, arising from the upper part of the 

 branchial aperture ; curves down parallel with the superior margin of the opercle ; passes 

 down behind the pectoral ; descends to the lower third of the body, thence running parallel 

 and near the edge of the abdomen ; passes through the tail, and may be traced to the extreme 

 tip : it is of a greenish yellow color. Head flattened between the eyes, becoming ridged on 

 the nape towards the dorsal fin ; compressed laterally, becoming more acute beneath. Its 

 length from the tip of the lower jaw to the point of the opercle, five and a half inches ; depth 

 of the head across the base of the pectorals, three inches. Eyes large, circular, prominent, 

 three quarters of an inch in diameter, and less than their diameter apart. Nostrils single, 

 large, vertically oval, near the eye. Lower jaw longest, with distant acute teeth, of which 

 the two anterior are largest, and when the jaw is closed, extend outside of the tip of the 

 upper jaw. The four or six posterior teeth on the sides are longest ; the intermediate shorter. 

 A fold of the skin across the interior of the upper jaw. The two anterior teeth are minute, 

 but immediately behind them are two long curved teeth, barbed at their tips ; these are re- 

 ceived into a cavity in the lower jaw. Posterior to these, on the interior edge of the jaw, 

 are from six to ten long, compressed, pointed and lancet-shaped teeth on each side. Minute 

 teeth on the palatines. Tongue free, subacute, smooth, except the asperities on its tip. 

 Seven branchial rays. Opercle ending in a point ; its tip extending beyond the base of the 

 pectoral fin, and, with its upper margin, ending in fibrous threads. 



The dorsal fin commences above the upper angle of the gill opening, slightly elevated in 

 the middle, where it is two inches high, and gradually disappears in the skin about three 

 and a half inches from the tip of the tail ; it is composed of flexible feebly spinous rays. 



