C18 CONTEIBUTIONS TO NORTH AMERICAN ICHTHYOLOGY — IV. 
rate, free from the isthmus; gills 4, a slit behind the fourth. Pseudo- 
bra iichim well developed, in a iiouch formed by a fold of the mucous 
membrane. Dorsal hu single, extending from the head to the tail, its 
rays all technically spinous, being neither articulated nor branched, 
but all very soft, flexible, and fragile; anal tin wanting; iiectorals 
slioi't; ventrals thoracic, the rays elongate, often less than I, 5 in ninn- 
ber; caudal flu either rudimentary or else divided into tvv'o parts, the 
up[)er and larger fan-shaped, directed obliquely upward from the slen- 
der tip of the tail. Bones very soft, the muscles little coherent. Py- 
loric coeca very numerous. Vertebrm in large number. Deep-sea Ashes, 
often of large size, found in most warm seas. Their extreme fragility 
renders them rare in collections, and the species are little known. 
Genera 3; species about 15. They have no intimate relation with any 
other of our families. 
{Trachyptcrlda Giinther, iii, 300-311. ) 
a. Ventral fins well developed; caudal present, not in the line of the axis of the 
body Traciiypterus, 331. 
331 .— 4r£«A€EI¥PTEISUS Gouan. 
King-of-the-IIerrinfjs. 
(Gouan, Hist. Poiss. 1770, 104: type Cepola tracli'jptcra Gmel.) 
This genus is characterized by the well-developed ventral fins, com- 
posed of 4-6 branched rays each, and by the presence of a long flin- 
shaped caudal fin extending obliquely upward and backward from the 
end of the long and slender tail; lower lobe of the fin little developed; 
the anterior rays of the dorsal tin are usually elevated, and separated 
by a notch from the rest of the fin; the fin rays and the lateral line 
are often armed with prickles. Deep-sea fishes of large size. 
rough; --e^ov, fin.) 
9@§. T. aSllvelllis Kner. — Eing-of-tlic-Sahnon. 
Bright silvery, with three large round black spots below the dorsal 
fin ; a fourth near the abdominal edge, a little below the first of the 
back. Anterior rays of the dorsal fin elevated ; the longest rays of the 
posterior part of the dorsal nearly as deep as the body; dorsal rays 
rough, a small siiine at the base of each of them; caudal fin with the 
erect lobe well developed, its outer rays longer and stronger than the 
intermediate rays; rays of the lower lobe short; skin prickljq the lat- 
eral line armed with small bony shields, each provided with a spine. 
