40 FISHES OF MASSACHUSETTS. 



semicircular scale of a beautiful purple color, at the commence- 

 ment of the lateral line : between this scale and the outer 

 angle of the naked space, at the posterior angle of the eye, a 

 band, half an inch or more in width, of smaller scales than 

 those of the body, passing obliquely upwards to the anterior 

 portion of the ridge of the back. The lateral line, commencing 

 at the upper angle of the operculum and passing obliquely up 

 to a point on a line with the fifth spine of the dorsal fin, curves 

 with the body to the base of the tail. 



The Dorsal fin, composed of twenty rays, twelve spinous, 

 twelve membranous, is received into a deep groove at its base ; 

 when this fin is not erect, the spines are scarcely visible, so 

 completely do they shut into this groove. Of the spines of 

 the dorsal fin, the third is the longest ; delicate filaments are 

 suspended from the extremities of the first three spines. Less 

 than two lines in front of the first dorsal spine when erect, lies 

 a strong spine projecting forwards, almost entirely enveloped 

 by the skin. 



The Pectoral fin, one fourth the length of the body, com- 

 mences on a line with the dorsal fin. 



The Ventral fin with six rays. 



The Anal fin shuts into a groove like the dorsal, and like 

 that fin is clouded with black spots. The three first rays of 

 anal, spinous. 



The Caudal fin forked. 



The fin rays are as follows : D. 24 ; P. 15 ; V. 6 ; A. 15 ; 

 C. 17. 



Mitchell describes this species as having twenty-six rays in 

 the dorsal fin : the specimens I have seen, had each but twen- 

 ty-four. 



