ACTPENSRR HUSO. 



their external edge. A single orifice, very open, in each oper- 

 culum. No rays to the membrane. 



THE SPECIFIC CHARACTERS. 



ACIPENSER HUSO. Mouth placed under the snout, small, and 

 without teeth. Eyes and nostrils in the sides of the head. 

 Cirri under the snout. Dorsal behind the ventral, and beneath 

 it. Caudal surrounding the extremity of the spine, and hav- 

 ing a salient lobe beneath shorter than its principal point. 



NATURAL HISTORY. 



STURGEON, Acipenser. A genus of large cartilaginous fish, 

 allied somewhat to the shark and ray, but differing essentially 

 in structure as well as in habits. There are several species 

 of the Acipenser, from all of which, however, isinglass is read- 

 ily obtained. 



The COMMON STURGEON, Acipenser sturio, is generally about 

 six feet long, but sometimes attains to the length of eighteen. 

 It inhabits the Northern European and American seas, mi- 

 grating during the early summer months into the larger rivers 

 and lakes, and returning to the sea again in autumn, after 

 having deposited the spawn. Its form is long and slender, 

 gradually tapering towards the tail, and covered throughout 

 the whole length by five rows of strong, large, bony tubercles, 

 rounded at the base, and terminated above by a sharp curved 

 point in a reversed direction. The body of the sturgeon is 

 more or less covered with bony plates arranged in longitudinal 

 rows, and the head is armed in a similar manner ; the snout 

 is long and slender, obtuse at the tip, and furnished beneath 

 at some distance from the end with four long, worm-shaped 

 cirri ; the mouth, placed under the elongated muzzle, is small 

 and toothless, and the palatal bones form the upper jaw; the 

 air-bladder is very large, and communicates by a wide open- 

 ing with the gullet. The pectoral fins are oval and middle- 

 sized ; the dorsal small, and situated very near the tail ; the 

 ventral and anal fins are also small, and placed nearly opposite 

 the dorsal. The tail is lobed or slightly forked, the upper lobe 

 extending far beyond the lower. The general color is cine- 

 reous above, with dusky specks, and yellowish-white beneath, 

 and the tops of the tubercles are of a similar cast. Though 

 generally considered as a fish of slow motion, it is sometimes 

 seen to swim with great rapidity, and also to spring out of the 



