GENERAL ZOOLOGY 



Fig. 18.12. Modern ray-finned fishes. A, an angel fish, Pomacanthus, of tropical marine 

 waters. B, Nassau grouper, Epinephe/us, in its natural reef habitat. C\ green moray, 

 Gymnothorax. D, the grotesque Sargassum fish, Histno, found in floating beds of Sargassum 

 weed which it strongly resembles. (.4 and B, underwater photographs by John F. Storr. 

 Others, photographs courtesy New York Zoological Society.) 



breathers, from which terrestrial vertebrates arose and whose lung breathing 

 has survived in the two independent lines of lung-breathing fishes, is 

 paralleled by other fishes coming out of the water in a variety of ways, in 

 response to the struggle for existence along recent shorelines. At the other 

 extreme are the fishes that have invaded the depths of the ocean and have 

 been modified no less remarkably than those that invaded the land, whose 

 descendants became the terrestrial vertebrates. 



The Tetrapoda or Four-Footed Vertebrates. Within recent years, 

 skeletal remains of very primitive amphibians have been found in the late 



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