FISHES OF HAWAIIAN ISLANDS. 
167 
Group SCOMBROIDEI. — -The Maekerel-like Fishes. 
Body variously formed, usually adapted for rapid swimming; the scales usually small and cycloid 
or wanting, sometimes transformed into rough or bony plates, but rarely ctenoid; lateral line various, 
usually undulate or with an anterior arch and a posterior straight part, at least not regularly arched; 
sometimes wanting; flesh in typical forms, firm, oily, and reddish in color, but in some cases pale and 
soft; caudal peduncle almost always slender and strong, the caudal fin, if present, more or less deeply 
forked, except in certain deep-sea forms and in aberrant families, the structure typically adapted for 
swift propulsion; dorsal fin usually long, the spinous portion generally shorter than the soft part, 
sometimes absent; the spines seldom very strong, sometimes not differentiated from the soft rays; 
anal fin always more or less similar to soft dorsal; ventrals thoracic, subjugular, or subabdominal, 
usually with one slender spine and 5 rays, sometimes many-rayed, sometimes rudimentary or wholly 
wanting; branchiostegals few, usually 7; gills 4, a slit behind the fourth; gillrakers various; gill-mem¬ 
branes usually separate, sometimes joined together, rarely attached to the isthmus; mouth and 
dentition various; skeleton firm or variously soft, the structure as in spinous-raved fishes generally; 
the shoulder-girdle attached to the; cranium by a distinctly forked post-temporal, which is not adnate 
to the cranium; no orbitosphenoid ; vertebra; varying from 24 to more than 100, the high numbers 
found in pelagic species; intestinal canal short. This group of mackerel-like fishes is not capable of 
exact definition, its deviations from the ordinary type of spiny-rayed fishes being various and in 
various directions, so that no set of diagnostic characters will cover them. The group is not a 
suborder, as the term is generally understood; it is incapable of simple definition, and in its 
divergence some members approach to other groups more nearly than to typical or even extreme 
members of their own. The group is, however, a somewhat natural one, as by the common consent 
of ichthyologists its different types have always been kept near each other in the system of classi¬ 
fication. 
a. Ventral tins with fewer than 8 soft rays, usually I, 5, sometimes wanting. 
b. Bones of snout and upper jaw prolonged into a distinct sword; vertebne about 21; ventrals and teeth 
wanting in the adult; scales obsolete. Xiphiidse , p. 167 
bb. Bones of snout not prolonged in a sword. 
c. Body fusiform or band-shaped, with many vertebrae (30 to 120), small or minute scales and dis- 
tinetly forked caudal on a slender peduncle (the fin sometimes wanting); dorsal and 
anal long, the spinous part of dorsal well developed. 
d. Caudal fin present. 
e. Soft dorsal and anal distinct from spinous part, the anterior rays forming a more or less 
distinct lobe; body moderately elongate, fusiform; caudal peduncle with a distinct 
keel; finlets always present; ventrals I, 5 . Scombridse, p. 168 
ee. Soft dorsal and anal more or less continuous with spinous dorsal, their anterior rays not 
forming a distinct lobe; ventrals rudimentary. Lepidopidse, p. 176 
cc. Body and fins various, not showing the combination noted under c. 
/. Vertebne 10 + 12 to 15 = 22 to 25; dorsal spines not long and filamentous; anal with 2 free 
spines in young. Caraiigidx, p. 179 
//. Vertebne 30 or more (in excess of 10 + 14); dorsal fin with a distinct spinous part; spinous 
dorsal little developed, of 3 or 4 weak and slender spines continuous with the soft rays; 
dorsal fin beginning behind the head; body ovate; scales firm, not very small . Bramidse, p. 202 
///. Vertebree 30 or more (in excess of 10 + 14); dorsal fin without spinous part, all the rays 
branched and articulate; dorsal beginning as a crest on the head; body oblong; scales 
very small. Coryptusnidx, p. 203 
Family LII. XIPHIID.4L—The Swordfishes, 
Fishes of great size, with the body elongate, naked, the young covered with rough granulations; 
upper jaw very much prolonged, forming a “sword,” which is flattened horizontally and composed of 
the consolidated vomer, ethmoid, and premaxillaries; teeth wanting in the adult, present in the young; 
dorsal fin long, usually divided in the adult, continuous in the young, without differentiated spinous 
part, each part composed of soft rays, the posterior portion much smaller than the anterior and placed 
on the tail, resembling the second dorsal of a shark; fin rays enveloped in the skin; anal fin divided 
in the adult; caudal peduncle slender, with a strong median keel; caudal fin widely forked in the 
adult; ventral fins entirely wanting; no pelvic arch; gills of peculiar structure, the lamina; of each 
