152 HISTORY OF THE FISHES OF MASSACHUSETTS. 



PALINURUS PERCIFORMIS, Dekuy. 

 The Black Pilot. 



(PLATE XIII. FIG. 3.) 



Rudder-fish, or Perch Coryphene, MITCHILL, Trans. Lit. and Phil. Soc. of N. Y., i. pi. 6, fig. 7. No description. 



" Corypkcena perciformis, MITCHILL, Amer. Month. Mag., n. p. 244. 



TracJiinotus argenteus, STOKER, Report, p. 53. 

 Palinurus perciformis, Black Pilot, DEKAY, Keport, p. 118, pi. 24, fig. 25. 



" " STOKER, Mem. Amer. Acad., New Series, II. p. 351. 



" " " Synopsis, p. 99. 



Color. Of a bluish-white color upon the sides, covered with minute black punctures, 

 the lower portion of the sides and abdomen of a lighter color ; the top of the head and 

 back mottled with black blotches. In the immature fish the color is a dark brown, varie- 

 gated with yellow patches. 



Description. The body of this fish is oblong. The head in length is equal to one 

 fourth that of the body ; a bony ridge is observed over the eyes ; the diameter of the 

 eyes is rather more than one fourth the length of the head. The operculum is large, 

 naked, of a horny texture, margined by a membrane. The preoperculum is strongly ser- 

 rated throughout, more conspicuously posteriorly. A depression exists upon the top of 

 the head between the eyes. The distance between the eyes is equal to twice the diam- 

 eter of the eyes. The nostrils are situated directly in front of the anterior superior angle 

 of the eyes ; the posterior is much the larger. The jaws are of equal length, with small, 

 sharp teeth ; the upper jaw descends abruptly. 



The lateral line commences high above the operculum, and, curving over the pectorals 

 to their extremities, pursues a straight course to the tail. 



The dorsal fin, whose fleshy portion is preceded by eight spinous rays, commences 

 back of a line opposite the posterior angle of the operculum, and is continued to the 

 fleshy portion of the tail. 



The pectorals are just beneath the posterior angle of the operculum ; they are as long 

 again as high. 



The ventrals are more than half the length of the pectorals ; their outer ray is spi- 

 nous. 



The anal fin arises just in the middle of the body, and is as long again as high ; this 

 fin is preceded by three spinous rays. 



The caudal fin is quite deeply lunated. . 



Length, about twelve inches. 



The fin rays are as follows : D. 8-22. P. 19 to 21. V. 1 - 5. A. 3 - 17. C. 16|. 



