HISTOKY OE THE FISHES OF JMASSACHDSETTS. 239 



The lateral line, wHch is quite indistinct, commencing on the side of the occiput, passes 

 obliquely backward to a line above the third branchial orifice, and then assuming a 

 straight line, runs the whole length of the body, and is lost upon the posterior extremity 

 of the caudal fin. 



The first dorsal fin is somewhat triangular, roimded anteriorly, with its posterior base 

 elongated and free. It is situated in the anterior half of the body. 



The second dorsal fin arises just anterior to the caudal fin. It is quadrangular, quite 

 small, having its anterior margin slightly rounded, and its posterior extremity prolonged 

 into a filament. 



The pectorals arise at the base of the fourth branchial orifice, and are romided ante- 

 riorly. 



The ventrals, of a quadrangular form, commence just back of the middle of the body* 



The anal fin commences on a line just in Jfront of the second dorsal, resembling 

 somewhat that fin in shape, but more deeply emarginated posteriorly. 



The upper lobe of the caudal fin is very long, and curved at its extremity, its 

 lower portion, a thin membrane, ends posteriorly in a small triangular expansion. 

 The lower lobe is much smaUer than the upper, and triangular. 



Length, two to twelve feet. 



Bemarhs. Although some slight discrepancies might be pointed out between our spe- 

 cies and that described by Valenciennes, I have but little doubt that they are identical, 

 and as such classify them. This species is exceedingly rare in our waters. In my ^^ Ee- 

 port/' published in 1839, 1 observed that ^' Dr. Yale had informed me that a species of 

 ZygsBua was found at Holmes Hole." In 'October, 1841, 1 had an opportimity to see a 

 specimen which had been brought to this city by Winslow Lewis, Esq., from Chatham, 

 Cape Cod, at which place it had been taken with a second specimen in a net This indi- 

 vidual I described in the second number of the fourth volume of the Boston Journal of 

 Natural History, for September, 1842. In 1851, 1 received a specimen from Provincetown, 

 firom Mr. Jonathan E. Smith, taken accidentally in a net Capt Atwood also saw some 

 half of a dozen of this species taken that season, one being seven feet in length. Previ- 

 ous to these, he had never seen but two or three, and those very small, in Massachusetts 

 Bay. He had, however, seen them south of Cape Cod in some abundance. In Septem- 

 ber, 1857, 1 received a specimen from Capt Atwood, taken at Provincetown, which is 

 above described, 



Massachusetts, Stoeer, New York, Mitchill, Dekay, Caribbean Sea, Bancroft. 

 a pj^-om Nantucket to Brazil,'' Dekay. [ 



