620 CONTRIBUTIONS TO NORTH AMERICAN ICHTHYOLOGY — IV. 
332.— aCOSTElJS Lockiugton, 
(Lockingtoii, Proc. U. S. Nat. Mus. ii, 63, 1830: type Icosfeiis cenigmaticus Lockiugton.) 
Body obloii"^, nmcli compressed tbrougliout, the head thicker than 
any part of the body. Dorsal outline rising rapidly to the origin of the 
dorsal tin, thence more regularly curved; the region at the base of the 
dorsal and anal strongly compressed; caudal peduncle slender, widened 
at the base of the fin. Mouth large, horizontal; maxillary narrow, 
reaching to beyond middle of eye. Teeth in jaws in one row, slender, 
sharp, closely and regularly set, those in the lower jaw largest; no teeth 
on vomer, palatines, or pharyngeals. Gill-rakers flexible, few; gill-mem- 
branes separate, fiee from the isthmus. Branchiostegals 6. Pseudo- 
branchim well developed. Lateral line conspicuous, continuous, de- 
curved, groups of small spines present along its entire length. No 
scales anywhere on body or fins. Fins rough, with small spinnles; a 
series along each ray, dividing as the ray branches; dorsal fin com- 
mencing above the axil of the pectoral, composed of 50-00 rays, which 
are all soft and flexible, some of the anterior unbranched; the fin low 
in front, increasing in height behind; none of the rays more than once 
forked; anal shorter than the dorsal, similar to it, of 35-40 rays; some 
of the anterior apparently undivided; caudal fin elongate, fan-shaped, 
the middle rays i)roduced; accessory rays numerous, procurrent; pec- 
torals with a fleshy base, fan-shaped, the middle rajs longest; veutrals 
thoracic, inserted just behind the pectorals, narrow, consisting of 1 
short subspinous ray and 4 long soft rays. Air-bladder large. Ver- 
tebrie numerous, the vertebral column extremely flexible and soft. 
Cranial bones tolerably firm; bones of the face and opercles very flex- 
ible. Deep-sea fishes, from the Pacific, (itzw, to yield, submit; 
bone — the “entire body being characterized by a want of firmness, as 
it can be doubled up as readily as a piece of soft, thick rag.”) 
06.'>. I. ae:a jgasialicus Lockiugton. 
Pellucid yellowish or brownish, with purplish spots and blotches of 
irregular form; the spots largest above, most numerous along the lat- 
eral line; fleshy bases of caudal and pectorals spotted; throat and gill- 
membranes with dark punctnlations; fins dusky, obscurely blotched. 
Longest ray of dorsal nearly reaching base of middle caudal rays. Eye 
0 in head, scarcely half the length of the snout or tlie width of the in- 
terorbital space; diameter of candal iieduncle about 5A in greatest 
depth. Dead 4; depth 3. D. 52-55; A. 37-40; V. 1, 4; Jait. 1. 110-120 
