ACIPENSERID.E. 19 



Order : CHONDROSTEI . 

 Family : AciPENSERlD^E. 



Key to Genera. 



A. Spiracles present ; snout subconic ; rows of bony shields distinct throughout ; the 

 tail not depressed nor mailed. — Acipenser. 



AA. Spiracles obsolete ; snout subspatulate ; rows of bony shields confluent behind dor- 

 sal so that the depressed tail is completely mailed. — Scaphirhynchus. 



Genus : Acipenser. 



Acipenser rubicundus Le Sueur. Lake Sturgeon ; 

 Ohio Sturgeon ; Rock Sturgeon. 



Body elongate, terete, tapering towards snout and tail. Snout long and 

 slender in young, becoming more blunt with age. Body covered with large, 

 rough, strongly hooked shields, which become smoother with age. Color 

 dark olive above, sides paler or reddish, with sometimes irregular dark spots. 

 Length 6 feet. 



This species occurs both in L,ake Erie and the Ohio river. 

 Those from the Ohio, formerly considered as belonging to a 

 separate species, A. maculosus, are now regarded as the young of 

 A. rubiaindus. "The Ohio river as far as Pittsburg," Rafin- 

 esque (Rafinesque made six species out of this and Scaphirhyn- 

 chus platorynchus, which he included in the same genus); Lake 

 Erie and Ohio river, Kirtland ; Lorain County, very common, 

 McCormick, 1892 ; abundant in the Ohio river, Henshall, 1888 ; 

 Lake Erie (west end), Kirsch, 1893. 



Genus ; Scaphirhynchus. 



Scaphirhynchus platorynchus (Rafinesque). 

 Shoveenose Sturgeon. 



Body slender, head broad, becoming suddenly broader just behind the 

 eyes. Snout flat and pointed. The body tapers gradually backward from 

 the head to the tail, the upper lobe of which ends in a long, slender filament. 

 Body protected by five rows of bony shields, which are keeled and hooked. 

 Color olive, paler below. Length 5 feet. 



' ' Very common in the Ohio, but seldom reaching as high as 

 Pittsburg," Rafinesque; "common in the waters of the Ohio," 

 Kirtland ; " common in the Ohio," Henshall, 1888. 



