76 



NORTHERN FISHES 



Figure i. A. Rock sturgeon, Acifenser julvescens, 23 inches long. B. Hackle- 

 back. Scaphirhijnchus platorynchus, 20 inches long. C. Northern longnose gar, 

 Lepisosteus osseus oxyurus, 24 inches long. D. Shortnose gar, Lepisosteus plato- 

 stomus, 20 inches long. 



200 pounds have been reported. The rock sturgeon may be distinguished 

 from the shovelnose sturgeon by its more pointed snout and by the 

 presence of a pair of spiracles, or openings, in the head, anterior to the 

 gills. The peduncle of the tail is short and heavy. 



In appearance rock sturgeon change greatly with age and size. The 

 young have sharp snouts and very rough shields with the spines strongly 

 hooked. The adults have blunt snouts and small, smooth shields, most 

 of which disappear with age. The color also changes considerably^: the 



