472 



COLLEGE ZOOLOGY 



406) are found in the marshes of Central Africa. They feed on 

 crustaceans, worms, insects, and frogs, and breathe with a pair 

 of lungs. During the dry summer season they burrow about 



FIG. 406. The African lung-fish, Protoplerus annectens. (From Sedgwick's 



Zoology, after Claus.) 



eighteen inches into the mud, where a cocoon of slime is secreted, 

 and the fish remains inactive, breathing with its lungs, and 

 living on fat stored in the kidneys and gonads, until the rainy 

 season comes again. 



The second genus of this family, Lepidosiren, has but a single 

 species, Lepidosiren paradoxa (Fig. 407), confined to the marshes 

 and swamps of South America. It feeds on algae, mollusks, 



FIG. 407. The South American lung-fish, Lepidosiren paradoxa. 

 (From Shipley and MacBride, after Kerr.) 



and other plants and animals, and comes to the surface to change 

 the air in its lungs. Like the African lung- fish, it hibernates in 

 the mud during the dry season. 



5. DEEP-SEA FISHES 



Many families of fishes contain deep-sea species, and about 

 thirty families of teleosts are known only from specimens taken 

 in the sea at depths of over a thousand fathoms. At this depth 

 conditions are quite different from those near the surface. 

 There is probably no sunlight below two hundred fathoms; the 



