ACIPENSEKID^. — CXV. 345 



* Rows of bony bucklers distinct throughout; spiracles present; 



snout rather narrow, sub-conical. . . Acipenseii, 1. 



** Rows of bony bucklers confluent behind, entirely surround- 

 ing the depressed tail ; no spiracles ; snout flattened, rather 

 broad, shovel-shaped. . ^ . . Scaphirhynchops, 2. 



/. ACIPENSER, Linnaeus. Sturgeons. 



* Marine species ascending rivers ; lateral shields 22 to 32. 



1. A. sturio, L. Common Sea Sturgeon. Sharp- 

 Nosed Sturgeon. Snout pointed, half the length of 

 head; dorsal shields 11 to 13; lateral shields 26 to 31; 

 D. 37 to 44: rays. Atlantic Ocean S. to Africa and West 

 Indies. (^4. oxyrhynchus^ Mit., the American form.) 



2. A. brevirostris, LeSueur. Blunt-Nosed Sturgeon. 

 Snout blunt, one-quarter length of head; dorsal shields 

 8 to 10; lateral shields 22 to 28; abdominal 8 to 10; D. 

 30 rays; skin with minute scattered prickles and stellate 

 ossifications. Cape Cod to Fla. 



** Species of fresh water; lateral shields 133 to 38. 



3. A. maculosus, I^eSueur. Rock Sturgeon. Bony 

 Sturgeon. Snout pointed, nearly as long as rest of 

 head; head 3-J- in length of body; bony shields large, 

 close together, 13 to 16 in front of dorsal, 33 to 38 on 

 sides, 9 or 10 on abdomen, all of them rough and strongly 

 radiated, with more or less hooked or incurved tips; skin 

 rough; D. 37 to 45. Great Lakes (?)^ Ohio R. and south- 

 ward. 



4. A. rubicundus, LeSueur. Red Sturgeon. Lake 

 Sturgeon. Head 4^ in length; eye 10 in head, nearly 

 midway; dorsal scutes 16 (to base of D), relatively small 

 and rather distant; lateral scutes 35; ventral scutes 9; 

 snout rather blunt, becoming more so with age, rather 

 shorter than rest of head; barbels nearer to end of snout 



