FAMILY STURIONIDJE ACIPENSER. 345 



Description. Body most elevated at the nape. Head flat, obliquely descending to the end 

 of the snout, and covered with rough radiated bony plates. Eyes round, with a vertical 

 pupil, and three inches apart, and the same distance from the end of the snout. Four barbels 

 arranged transversely under the snout, and nearer the snout than to the mouth. Dorsal series 

 of tubercles nine in number, broad, flat, little elevated ; the two posterior ending in a point. 

 The lateral series composed of thirty-nine lozenge-shaped oblique plates, equidistant between 

 the dorsal and abdominal outlines, and running upon the tail ; rudiments of plates behind the 

 dorsal fin. Opercle radiated ; small plates behind the eyes, extending along the borders of 

 the snout ; a semicircle of small tubercles below the eyes. Skin covered with minute prickles 

 in patches, which are obvious to the touch. Tail covered with lozenge-shaped tubercles. 

 The dorsal fin wider than high, broadly excavated ; with its posterior two-thirds above the 

 base of the anal. Pectorals long and pointed, with numerous rays. Anal higher than wide ; 

 its posterior margin vertically truncate, slightly concave. Caudal fin stout. 



Color, of the back, yellowish red ; of the sides, olivaceous red. 



Length, 48" 0; of the head, 6-0. 



Fin rays, D. 40 ; P. 50 ; V. 28 ; A. 22. 



Lesueur, who first described this species, has noticed two varieties. The first has the 

 head flat and shorter, with twelve dorsal and thirty-four lateral tubercles ; length twenty- 

 nine inches. The second variety occurs in the Ohio ; the head convex ; dorsal tubercles ob- 

 long, and fourteen in number ; the lateral tubercles thirty-four, irregularly formed and placed ; 

 length four feet. 



This species occurs in Lakes Ontario, Erie, and all the upper lakes. Dr. Richardson states 

 the northern limits of the Sturgeon in North America, to be about the fifty-fifth parallel of 

 north latitude. 



THE SHORT-NOSED STURGEON. 



ACIPENSER BREVIR09TKIS. 



The Round-nosed Sturgeon, A. sturio. Mitchill, Trans. Lit. and Phil. Soc. Vol. 1, p. 461. 

 Acipenser brevirostrum. Lesceur, Trans. Am. Phil. Soc. New Series, Vol. 1, p. 590. 



Characteristics. Snout short and blunt. Dorsal series of tubercles nine to twelve ; lateral 

 series twenty-three to twenty-nine, oblong, oblique. Length two to five 

 feet. 



Description. Head large and convex. Snout short, subacute, depressed between the eyes. 

 The skin appears smooth, but is covered with small spinous asperities, scattered equally over 

 the skin. Auricular orifices an inch and a half behind the eyes. Length of the head to the 

 total length as one to five. Four flat barbels under the snout, disposed in pairs, and nearer 

 the nostrils than to the end of the snout. The dorsal series composed of nine oblong radiated 

 and carinated tubercles, with another at the base of the dorsal fin. Lateral series twenty- 

 three to twenty-nine, irregular, oblong, oblique, with a slight keel on the posterior ones. Ab- 



Fatjna — Part 4. 44 



