Page 11 - Fish and Amphibians (Britannica Illustrated Science Library)
P. 11

General Characteristics  CROCODILE FISH FIN                   EARLIEST FORMS  8-9       CARTILAGINOUS FISH  14-15
            This fish, which lives in
            waters with abundant coral                         DISTINGUISHING FEATURES  10-11  ANATOMY  16-17
            reefs, can grow up to 21                           BONY FISH  12-13
            inches (54 cm) long.








































































 ish were the first vertebrates  fish, the earliest fish had no scales, fins,  water and salt water. Their bodies are  these complex creatures normally
 with bony skeletons to appear  or jawbone, but they did have a type of  generally streamlined, being covered  breathe through gills that capture
 on the Earth. They doubtless  dorsal fin. Over time they have been  with smooth scales and having fins that  oxygen dissolved in the water, and they
 form the most numerous group  changing in form and size to adapt to  enable them to move with energy,  are cold-blooded.
 F of vertebrates. Unlike today's  different environments, in both fresh  direction, and stability. In place of lungs,
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