HISTORY OF THE FISHES OF MASSACHUSETTS. 55 



The second dorsal, situated upon the posterior half of the head, is of a fuliginous color, 

 margined with white ; it is nearly three times as long as high ; back of this second dorsal, 

 occupying the space between it and the tail, are five finlets, the fifth of which is usually 

 the largest. 



The pectoral fins, of a dark color, having at their base beneath, a black blotch, arise 

 back of the upper third of the operculum. Their length is equal to about one third their 

 height. 



The ventrals arise back of the pectorals, and likewise have beneath them a black spot 

 at their base ; save the tinge given them by this spot, they are of a flesh color in the 

 fresh fish, but soon become the color of the abdomen after death. The first ray is very 

 strong. All the rays are subdivided at their middle, and again divided into smaller por- 

 tions at their extremities. 



The anal fin arises directly back of the anus, which is situated opposite the origin of 

 the second dorsal. At the commencement of this fin is a short spine ; this fin is slightly 

 shorter than the second dorsal, and is of the same color as the abdomen. Back of this fin 

 are six finlets ; that next the anal fin appearing at first sight to be a portion of the fin. 



At the base of the caudal fin are situated two longitudinal carinse, extending the whole 

 length of the fleshy portion of the tail ; the outer rays of the caudal fin are much the 

 larger ; their articulations are very direct ; the fin is deeply forked ; its extremities are 

 margined with white ; the distance between the extremities of the caudal rays, when 

 expanded, is equal to the length of the head. 



The fin rays are as follows : — D. 10 - 12. P. 17. V. 5. A. 12. C. 20. 



Remarks. Mitchill described the mackerel which visit our shores in the spring, and 

 those which are taken in the autumn, as distinct species. Dekay coincides with him in 

 his opinion. In my " Report " I considered them as one species, agreeing with Richard- 

 son, who observes : " The only differences between S. grex and vemalis seem to be in 

 their size and color, and they are very probably different ages of the same species." In 

 my " Synopsis " I reluctantly yielded my opinion to that of Dekay, and described the 

 two species. Satisfied that my early impressions were correct, I again unite them, 

 remarking, as in my " Report," that " I have examined with much care the mackerel 

 which are brought to our market, and the differences are too slight between them to con- 

 stitute distinct species." 



This beautiful species is one of the most valuable fishes which frequents our waters. 

 From the 10th of May to the 15th of June, they appear at the entrance of Massachusetts 

 Bay, having been a few days previous at Nantucket and Vineyard Sound. Nine tenths 

 of those which are first seen are males, and they are all large, but poor, weighing from 



