7-2 XIPHIID.?: XIPHIAS. 
419 
the longer. Lateral line wavy and irregular, descending posteriorly. 
Head 4^ in length; depth 5|. D. YIII-I, 2G; A. II, 25. L. 5 feet. 
In all warm seas, occasional on our Atlantic coast in summer. 
( Gastero^teus canadus Linn. Syst. Xat. : Elacate atlanticus Cuv. & V’al. viii, 334 : Elacate 
nigra Giintlier, ii, 375 ; Holbrook, IcLth. S. Car. 97.) 
Family LXXIL— XIPHIID^. 
{The Sicord-Jishes.) 
Scombroid fishes of great size, with the body elongated, naked or 
covered with rough rudimentary scales, and the upper jaw very much 
prolonged, forming a “sword,’’ which is comiiosed of the consolidated, 
vomer, ethmoid and premaxillaries. Teeth small and rudimentary, or 
wanting. Dorsal fin long, usually divided in the adult, continuous iu 
the young, without differentiated spinous part, the posterior portion 
much smaller than the anterior. Anal fin similarly divided in the 
adult. Caudal peduncle slender, keeled. Ventral fins thoracic, incom- 
plete or entirely wanting. Caudal fin widely forked in the adult. Gills 
of peculiar structure, the lamiuie of each arch joined into one plate 
by reticulations. Gills 4, a slit behind fourth ; gill-membranes separate, 
free from isthmus. Pseudobranchiie jiresent. Branchiostegals 7. Air- 
bladder present. Pyloric coeca very numerous. V ery young individuals 
differing much from the adults; the fins high, both jaws iirolonged into 
a beak, and the head armed with long spines. Genera 3; species about 
5; powerful fishes, inhabiting the open seas, most of them valued as 
food. {Xij}]iiid(c Giinther, ii, 511-514.) 
a. Ventral fins entirely wanting ; teeth none. {Xijyhiina;) Xiphias, 209. 
aa. Ventral fins present ; teeth small. {Histio2}horin(E.) 
1). Ventral rays united into one ; dorsal fin low Tetr.\pturus, 210. 
bb. Ventral rays three ; dorsal very high Histiophorus, 211, 
209.— XIPHIAS Linnajus. 
Stcord-Jishes. 
(Linn. Syst. Nat. : type Xiphias gladius L.) 
Sword-fishes without teeth and without ventral fins. Body somewhat 
compressed. Dorsal fins 2, the anterior beginning opposite the gill- 
openings, falcate and elevated, its height rather less than that of the 
body ; second dorsal very small, on the tail, opposite the small second 
anal. In the young, teeth are present and the two dorsal fins are con- 
nected, the fin being elevated as in the species of Histiophorus. First 
anal similar to first dorsal, but smaller, less falcate, and far behind it; 
