236 Field Museum of Natural History — Zoology, Vol. VII. 



Lake Sturgeon 



Acipenser rubicundus Le Sueur. 



Head 3.1 to 3.8; depth 7 to 7.8; D. 35 to 36; A. 25 to 28. Body 

 elongate, cylindrical; snout subcorneal, convex above, flattened be- 

 low, overhanging the mouth, 2 to 2.4 in head; eye small, ^.;^ to 4.2 in 

 head; lips 2-lobed; gill membranes united to the isthmus; barbels, of 

 nearly equal length; dorsal scutes 12 to 16; lateral 32 to 43; ventral 

 8 to 10. These almost entirely disappear in specimens of 150 pounds 

 weight; upper caudal lobe the longer, not produced into a filament;' 

 caudal fulcra numerous. 



Color dark olive above; sides paler to reddish; body often with 

 irregular blackish blotches. Length 6 to 12 feet. 



. Fig. 17. Lake Sturgeon. 



Acipenser rubicundus Le Sueur. (After Forbes and Richardson.) 



This sturgeon inhabits large streams and lakes of the Upper Mis- 

 sissippi Valley, the Great Lakes and northward. About twenty-five 

 years ago it was abundant in the lakes near Chicago. There was 

 no market for it then and many were buried in the sand to get rid of 

 them. At present it is quite rare and sells in the market for double 

 the price of the best fish found in Lake Michigan. The sturgeon 

 spawns in the spring. 



Lake Michigan, Chicago, Illinois; Lake Michigan, Millers, Indiana; 

 Lake Michigan, Pine, Indiana; Lake Michigan, Edgemoor, Indiana. 



Order Rhomboganoidea. 



The Garpikes. 



Skeleton ossified; vertebrae connected by ball and socket joints, 

 the cavity of each vertebra being posterior; ventral fins abdominal; 

 fins without spines; opercular skeleton complete; maxillary present; 

 air bladder cellular, lung-like, opening into the side of the oesophagus. 



