FISHES OF THE GULF OF MAINE 



369 



THE RUDDERFISHES. FAMILY CENTROLOPHIDAE 



The closest affinities of the rudderfishes are 

 with the mackerel-like fishes. They have moder- 

 ately stout bodies, short blunt snouts with convex 

 profiles, and a moderately deep caudal peduncle 

 without longitudinal keels. The single dorsal fin 

 extends from over the pectorals to the caudal 

 peduncle; the front part of the dorsal is spiny, 

 either reduced to a few flexible spines covered over 

 by the skin so that it is hard to find them, or 

 represented by several detached spines so short 

 that they might be overlooked, and preceding the 

 much longer soft-rayed part of the dorsal. The 

 tail fin is only slightly emarginate; the anal fin is 

 similar to the dorsal in shape but much shorter; 

 the ventrals are below the pectorals, and are 

 smaller than the latter. The mouth is small, with 

 small teeth in the jaws. Only two species are 

 known off the Atlantic coast of the United States. 



KEY TO GULF OF MAINE SPECIES 



1. The single dorsal fin is preceded by 6-8 short 



detached spines; the sides of the head are 

 scaly Barrelfish, p. 369 



2. The dorsal fin is not preceded by any detached 



spines; there are no scales on the sides of the 

 head Black ruff, p. 370 



Barrelfish Palinurichthys perciformis 

 (Mitchill) 1818 



Logfish; Rudderfish; Black pilot 

 Jordan and Evermann, 1896-1900, p. 964. 



Description. — The reduction of the spiny portion 

 of the dorsal fin of the barrelfish to 6 to 8 short 

 detached spines, with very small triangular fin 

 membranes, closely followed by a long soft-rayed 

 dorsal fin, marks the barrelfish from all other Gulf 

 of Maine fishes, except for certain of the pompano 

 tribe. The caudal fin of the barrelfish is only 

 slightly emarginate instead of deeply forked and 

 its caudal peduncle moderately stout and without 

 keels instead of very slender. It suggest a tautog 

 remotely in general appearance, especially in its 

 rather stout body (about two-fifths as deep as long, 

 not including the caudal fin), very bluntly rounded 

 nose, convex forehead, and small mouth. But its 

 rudimentary spiny dorsal fin and forked caudal fin 

 are ready field marks to distinguish it. The soft 

 dorsal fin (20 to 22 rays) arises about mid-way from 

 tip of snout toward base of caudal fin; the anal 

 (16 or 17 rays) somewhat farther back. Both 

 these fins are moderately high and they taper 

 slightly from front to rear. The anal is preceded 

 by three short spines so nearly imbedded in the 

 skin as to be hardly visible. Both the ventrals 

 and the pectorals are large with rounded tips. The 

 top of the head is scaleless but the sides of its 

 head and the body are clothed with small rounded 

 scales. 



The presence of the dorsal fin-spines and the 

 scaliness of the sides of its head distinguish it 

 from its close relative the black ruff (fig. 196). 



Figure 195. — Barrelfish (Palinurichthys perciformis). After DeKay. 



