HISTORY OF THE FISHES OF MASSACHUSETTS. 431 



ACIPENSER OXYEmCHUS, MitcMU. 



The Sharp-nosed Sturgeon. 

 (Plate XXXV. Fia. 4.) 



Acipenser Oxi/rlnchus, Sharp-nosed Sturgeon ^ Mitch., Tians. Lit. and Phil. Soc. of N, Y., i. p. 462. 



" " Lestteur, Trans. Amer. Phil Soc, New Series, i. p 394. 



" '* Sharp-nosed Sturgeon i Storer, Report, p 178. 



*' " " '<■ Dekat, Report, p. 346, pi. 58, fig. 189. 



'* '* Ayres, Fishes of Brookhaven, L. I., Bost. Journ. Nat Hist., iv. p. 287. 



" " LiNSLET, Cat. of Fishes of Connecticut, Amer. Journ. Science. 



" ** Storer, Mera. Amer. Acad., New Series, ii. p. 499. 



" " " Synopsis, p. 247. 



Color. Of a grayish-brown color above ; silvery npon tlie inferior portion of the 

 sides ; white beneath. Pupils black, irides yellow. 



Description. Body elongated, pentagonal. Entire surface granulated, excepting 

 that occupied by five longitudinal rows of flattened plates, of the same structure 

 as the covering of the head, but of a lighter color. The largest plates form the 

 dorsal ridge ; in younger specimens these plates are compressed at their sides, and 

 terminate above in strong, sharp, recurved spines; while in this the spines on the 

 dorsal ridge in some plates are obsolete, and the w^hole crest a mere sharp edge, 

 and are obvious only on a few of the plates ; radiating lines are distinctly seen 

 running from the centre of these scales to their circumference ; this row is com- 

 posed of ten plates. In the specimen formerly described by me, measuring two 

 feet and three inches in length, this row contained twelve plates. The first are 

 the largest; that at the commencement of the dorsal fin by far the smallest; be- 

 tween the dorsal and caudal fins are situated four plates. In the specimen de- 

 scribed in my " Report " two quite small plates were seen just back of the dorsal, 

 forming a pair; next to these a much larger one, and, lastly, an elongated one at 

 the commencement of the caudal fin. 



A second row of bony plates, twenty-eight in number, placed obliquely, com- 

 mences just back of the operculum, situated where the lateral line is usnally ob- 

 served in fishes, and is continued to the base of the tail ; these plates are narrowed 

 to a point at their upper extremities, obtuse at their lower extremities, widened in 

 their centres, and, like the former, are crowned by spines, more or less prominent, 

 from the bases of which radii diverge. The posterior plates are much the smaller. 



Beneath this row, just back of the pectorals, commences a third row of plates, 

 eight in number, placed vertically, larger than those of the last row. 



The head is flattened above, slightly depressed between the eyes, and terminates 



