452 CONTRIBUTIONS TO NORTH AMERICAN ICHTHYOLOGY IV. 
and ventral outlines about equally curved. Snout very blunt, rounded 
in proiile. Mouth small, the maxillary not reaching the orbit. Caudal 
peduncle very short; anterior rays of dorsal and anal little elevated. 
Lateral line high, a series of conspicuous pores above it near the base 
of the dorsal. Pectorals much longer tliau head. Gill-rakers rather 
long, § diameter of the eye, which is 4 iu head. Head 4; depth 2^. 
1). Ill, 45; A. Ill, 38. L. 10 inches. Maine to Cape Hatteras; very 
abundant. 
(Peck, Mem. Auier. Acad, ii, 48: Ehombtis cryptoHus Ciiv. & Val. is, 408; Gunther, ii, 
398.) 
233. — I^IRUS Lowe. 
Rudder -jlslies. 
(PaUnin-KS DeKay, preoccupied in Crustacea: Palinurivlithys Gill: Pam?>ic?as Giiuther. ) 
(Leiriis Lowe, Proc. Zodl. Soc. Loud. 1839, 82: type Leirus henmtti Lowe = Centroloplius 
ovolis C. & V.) 
Body ovate, compressed, more elongate and less compressed than in 
Stromateus. Profile very blunt and convex. Mouth moderate; maxil- 
lary narrow, with a small supplemental bone; premaxillaries protrac- 
tile, little movable. Jaws nearly equal, each with about one series of 
small, slender teeth; no teeth oil vomer or palatines. Preoperculuin, 
interoperculum, and suboperculura finely serrated. Gill-rakers long; 
gill-membranes separate, free from the isthmus. Scales small, smooth ; 
larger, thicker, and more adherent than iu Stromateus. Cheeks scaly. 
Pins rather low; dorsal fin long, iireceded by C-8 short but rather 
strong spines, the last ones connected by membrane, the others nearly 
free; anal fin similar but shorter, preceded by 3 spines, which, like the 
dorsal spiues, are nearly imbedded in thick skin ; vertical fins densely 
scaly towards their bases ; caudal fin emarginate ; caudal peduncle 
stout; ventral fins large, thoracic, I, 5; pectoral fins moderate, rounded 
or falcate. Two species, differing from the European genus Centroloplius 
chiefly in the development of the dorsal si)iues, which in the latter genus 
are indistinguishable from the soft rays. [Xstpix;, thin.) 
713. perciforinis (Mitch.) J. & G. — Pndder-fish. 
Blackish green, everywhere dark, the belly scarcely paler and not 
silvery. Eye rather large, with an adipose eyelid, its diameter nearly 
equal to the snout, 4.1 in head. Maxillary reaching to opposite front 
of pupil. Top of head naked, covered with small mucous iiores. Pec- 
torals nearly as long as head. Head 3J ; depth 2^. D. VII, I, 21; A. 
