101. ICOSTEID^E. 
619 
Head 7; depth 7. D. 7, IGl) to 190; C. u-5; P. 11; V. 7. {G'lUiUier.) 
Described troin Valparaiso, Chili. A young speciiueu examiued by us 
fj-om Sauta Cruz, Cal., agrees iii essential respects, except that the skin 
^s entirely smooth. The prickles are perhai)s acquired with age, other- 
wise ours may be a diifereiit species. Two specimeus of TracJnjpterus 
have also beeu takeu in Puget Sound, but they hav e not been preserved. 
(Kuer. Wieu. Sitzimgsber, xxxtv, 437, 1850, t:if. 1; Gauther, iii, 303.) 
Family CL— ICOSTEIDa]. 
{The Ronqinls.) 
Body oblong, compressed, naked or covered with small ctenoid or 
cycloid scales. Head moderate, not externally bony, the opercles un- 
armed. Mouth moderate, terminal; premaxillary protractile or not; 
maxillary moderate, without supplemental bone. Teeth .^mall, in b inds 
or in single series; vomer and palatines with or without teeth. No bar- 
bels. Lower pharyngeals separate. Branchiostegals G or 7. Gill-open- 
ings wide, the membranes free from the isthmus ; gills 4, a slit behind the 
fourth; gill-rakers slender, l^seudobranchim large. Pyloric coeca few. 
Air-bladder present. Lateral line present. Dorsal tin very long, con- 
tinuous, without distinct spines; anal long, without spines; caudal tin 
convex; ventral fins thoracic or subjugiilar, separate, but very close 
together, T, 4, or I, 5; pectorals rounded, sometimes tleshy at base. 
Vent normal, without papilla. Skeleton more or less soft and cartila- 
ginous. This group, as at present constituted, is composed of three 
very diverse genera, each of a single species, inhabiting the deeper 
waters of the North Pacific. It is probably most nearly related to the 
IlaJacanthidcej from which it is distinguished by the presence of pyloric 
coeca and by the non-labroid dentition. 
(ZcasteidcB Jordan & Gilbert, Proc. U. S. Nat. Mas. 18S0, 306.) 
a. Body naked, lateral line and fin rays beset with groups of spinales; skeleton not 
ossified. (Icosteinw.) 
b. Air-bladder present; teeth in jaws only, in single series, very slender; ventrals 
thoracic, 1, 4; caudal peduncle slender Icosteus, 332. 
aa. Body covered with small scales ; no spinules ; air-bladder wanting or rudimentary ; 
ventrals 1, 5. 
c. Skeleton imperfectly ossified ; lateral line median. {leichthnina;.) 
d. Teeth in a single series, minute, in jaws only; ventrals thoracic; caiuhil pe- 
duncle slender Icichthys, 333. 
cc. Skeleton ossified ; lateral line near the back. (Bafhumasterina:.) 
e. Teeth in bands, rather strong, on jaws, vomer, palatines, and pharyngeals; 
ventrals snbjugular; caudal peduncle not slender Bathy.masteu, 334. 
