19. Color grayish; ascending streams from the Atlantic 



Acipenser oxyrhynchus Mitchill Common Sturgeon 

 Color greenish, with a stripe lengthwise along each side and along the 

 mid'ventral line; ascending streams from the Pacific 

 Acipenser acutirostris Ayres Green Sturgeon 

 {Acipenser medirostris Ayres) 



20. Scales rounded; eastern and central states; Family Amiidae 



Amia calva Linn. River Dogfish, Bowfin 

 Scales rhombic; mouth in the form of a narrow beak full of sharp teeth; 

 Family Lepisosteidae Gar Pikes 21. 



21. With two rows of large teeth on each side of upper jaw in adults; tail 



fin with many small dark spots; south-central states 



Atractosteus spatula (Lacepede) Alligator Gar 

 (Atractosteus tristoechus (B. &? S.) ) 

 Adults with one row of large teeth on each side of upper jaw; tail fin 

 with several large dark spots (about the si2;e of the eye) 22. 



22. Least width of beak less than one-fifteenth of its length; caudal peduncle 



longer than depth of body; eastern and central U. S. 

 Lepisosteus osseus (Linn.) Long-nosed Gar 

 Least width of beak more than one-tenth of its length, in the adult; 

 caudal peduncle as long as depth of body; Mississippi Valley 23. 



23. Top of head spotted; usually less than fifty-nine scales in the lateral line 



Cyhndrosteus agassmi Dumeril Spotted Gar 

 Lepisosteus productus Cope 

 No spots on top of head; usually more than fifty-nine scales in lateral 

 line 



Cyhndrosteus platostomus (Raf.) Short-nosed Gar 

 Lepisosteus platostomus Raf. 



24. With both eyes on one side of the head; body m.uch flattened sideways, 



with one side dark colored and one side light colored; ascending 

 streams from the Atlantic and Gulf coasts; Family Achiridae 

 Achirus fasciatus Lacepede Sole 

 Not so 25. 



25. With a median chin barbel; dorsal fin extending almost the length of the 



back and divided into a short anterior and a long posterior section; 

 pelvic fins inserted before the pectorals; northeastern and north-central 

 states; Family Gadidae 



Lota maculosa (LeSueur) Burbot, Ling, Fresh-water Cod 



Lota lota maculosa (LeSueur) 

 Not so 26. 



26. With an apparently scaleless skin and with four to eight long barbels 



around the mouth; Family Ameiuridae Catfishes 27. 



Not so 46. 



27. Posterior margin of adipose fin (a small flap of skin without any support- 



ing rays, between the dorsal fin and the tail) joined to back 28. 



Posterior margin of adipose fin free 35. 



260 



