LUNG-FISH. 



the common garpike. [n ol h 

 however, as in the A.mia and Dip- 

 noans, the Bcales are rounded or 

 cycloid. The me ( Fig. I 



hav< I be snout long and pointed, 

 with the mouth underneath, and 

 toothless, while the body is pro- 

 tected by very large scales. Aci- 

 penser sturio is the common sea- 

 sturgeon of our coast, ascending 

 rivers. The shovel-nosed sturgi 

 Scaphirhynchops platyrhyncli 

 has a spade-like snout, h inhab- 

 its the waters of the Mississippi 

 \ alley. 



The singular spoon-bill, Polyo- 

 don folium (Fig. 194 ). is 6ve feet 

 long, smooth-skinned, lias a snout 

 one third as long as the body, and 

 spatulate, with thin • It has 



a \<r\ wide mouth, with minute 

 teeth, and lives on small ( Irus- 

 tacea. It abounds in the Missis 

 Bippi and its larger tributaries. 



The Dipnoi or lung-fishes are 



called from the facl thai often 

 being in pools and streams liable 

 to dry up, thej breathe air directly, 

 having true lungs, like those of 

 frogs, as well as gills. From the 

 nature of their brain and 3-cham- 

 bered heart, the Dipnoans are quite 

 differenl from all other fishes, while 

 on the other hand t in notocord 

 i- persistent. 



The body of the Dipnoans is 

 Bomewhal eel-shaped, though not 

 very long in proportion tojts thick- 



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