2R. ACIPENSERIDiE — ACIPENSER. ' 87 



hooted spine. Skin very rongh. Snout about as in A. transmontanus, 

 sharp in the young, becoming blunt with age, usually rather shortei 

 than the rest of head. Barbels nearly midway between snout and 

 nioutli. Gill-rakers scarcely higher than broad, about 17 in number. 

 Upper lobe of tail with some scattered plates. Caudal fulcra not en- 

 larged. Lower lobe of caudal short and blunt, little more than half the 

 length of the upper. Dorsal plates 10 5 lateral 28-30 5 ventral 9. Anal 

 fin about half below the dorsal. D. 37; A. 30. Depth 7} in length; 

 head 4|. Pacific coast, ascending the rivers from San Francisco north- 

 ward, reaching a large size. Less abundant than A. transmontanus; 

 not uspd for food, being reputed poisonous. 



(Ayres, Proc. Cal. Acad. Nat. Sci. i, 15; Giinther, viii, 342: Jcipenser agassizi Giiutlier, 

 viii, 344 : Acipenser acutirosiris Giintlier, viii, 344 ; not of Ayres.) 



77. A. rHbiCHilidMS Le Sueur. — LaJce Sturgeon; Ohio Sturgeon; Black Sturgeon; 

 Stone Sturgeon ; L'ock Sturgeon. 



Blackish above, sides paler or reddish. Body comparatively elongate ; 

 snout slender and long in the young, becoming quite blunt with age, 

 when it is considerably shorter than the rest of the head; shields large, 

 rough with strongly hooked spines, becoming later comparatively 

 smooth. Skin with minute rough plates. Ventral shields growing 

 smaller with age, and finally deciduous. Dorsal shields 13 (11-10); 

 lateral shields (34) 30-39; ventral ])lates 8-10. D. 35; A. 26. L. 6 

 feet. Weight 50 to 100 pounds. Mississippi Valley, Great Lakes, and 

 northward. Our common fresh- water sturgeon, usually not descending 

 to the sea. 



(Le Suenr, Trans. Amer. Phil. Soc. i, 1818,388: Acipenser maculosus Le Snenr, Trans. 

 Amer. Phil. Soc. i, 393: Acipenser ruperiianus Kicbardsou, Fauna Bor.-Amer. iii, 311: 

 Acipenser carbonarius, Iwvis, and rhynchwus Agassiz, Lake Superior, 271, 270: Acipenser 

 ruhicundus, maculosus, and liopcltis Giintlier, viii, 338, 339, 341 ; Milner, Eept. U. S. Fish 

 Com. l&72-'73,67.) 



■78. A. brcvirostris Lc ^ui^nr.— Short-nosed Sturgeon. 



" Snout very short and obtuse, about one-fourth of the length of the 

 head. Barbels short, simple. Osseous shields rather small and distant 

 from one another, finely radiated and granulated ; 8-10 on the back, 

 22-28 on the sides, G-8 along the abdomen. Skin very sparingly cov- 

 ered with minute prickles and very small scattered ossifications. The 

 greater part of the anal below the dorsal. D. 30." {Giinther.) Cape 

 Cod to Florida. 



(Lo Sueur, Trans. Amer. Phil. Soc. i,390; Giinther, viii, 341.) 



