126 HISTORY OF THE FISHES OF MASSACHUSETTS. 



are of a dark-brown, which, after death, changes to a greenish hue. Head of a dark 

 slate-color above ; opercula, a pale dull yellow. Sides of a greenish-yellow, with golden 

 reflections. Abdomen in front of ventrals nearly white, towards anal fin slightly 

 pinkish. Body marked with four or five faint transverse bands. Dorsal and caudal 

 fins color of the back. Pectorals and ventrals reddish, edged with dark-brown. Anal 

 fin in some individuals color of pectorals and ventrals, in other specimens of a bluish 

 or purplish brown. 



Description. Body compressed laterally, convex in front of dorsal fin ; this con- 

 vexity commences suddenly at the occiput, and is greatest at the origin of the dorsal. 

 Greatest depth of fish equal to about one fourth its length. Scales with very distinct 

 striae ; when plucked from the fish, they are quadrangular and exhibit concentric 

 lines passing across the stria? ; exceedingly delicate concentric lines are seen over the 

 entire scale. The head, which is smooth, is less than one fifth the length of the fish. 

 Snout short, rounded. Eyes moderate. Nostrils double, separated by a loose mem- 

 brane, the posterior the larger. Mouth small, lunated. At some seasons of the year, 

 between the eyes and snout on each side of the head are four prominent spines having 

 broad fleshy bases ; the upper anterior prominences the largest, and the upper 

 posterior the smallest. Beneath the first spine a smaller one is seen ; and directly 

 back of it a third nearly as large as the first. These first three form a triangle. Just 

 above the third prominence and in front of the upper anterior angle of the eye, and 

 between the nostrils and the eye, is a fourth prominence smaller than the others. In 

 some individuals, the spinous parts are removed and the bases remain as hard tubercles ; 

 sometimes the bases themselves are removed, and while the points from which they were 

 thrown off in some specimens are scarcely perceptible, in others a distinct excavation 

 is seen. Sometimes one or more tubercles are missing in the same individual. Dekay 

 remarks that this species has " three to five tubercles on each side." I have never met 

 with more than four. 



The quadrangular dorsal fin commences upon the anterior half of the body. 



The pectorals arise just back of the posterior inferior angle of the operculum ; they 

 are rounded when expanded. 



The ventrals, which are very nearly as high as the pectorals, are situated opposite the 

 anterior half of the dorsal fin. 



The anal fin is deeply emarginate ; its third and fourth rays are the longest. 



The lower lobe of the caudal fin is slightly longer than the upper. 



The fin rays are as follows : — D. 16. P. 16. V- 9. A. 10. C. 18. 



Length, seven to twelve inches. 



