XV111 



GIANT FISHES, WHALES AND DOLPHINS 



blood is separated from the surrounding water only by a 

 delicate membrane. As the water bathes the plates, the 

 blood absorbs the necessary oxygen, and at the same time 

 liberates the waste products from the bodv in the form of 

 carbon dioxide. 



Fig. 4. — Skull of a Whalebone Whale (Californian Grey Whale). 



Skull of a Toothed Whale (False Killer Whale). 



The principle of respiration is essentially the same in all 

 fishes, but the form and arrangement of the gills is somewhat 

 different in the Selachians and the Bony Fishes ; these differ- 

 ences are illustrated in the accompanying diagrams (Fig. 6). 

 Briefly, in Selachians, the walls of the gullet are perforated on 

 each side by a row of from 5 to 7 narrow openings, the internal 

 gill-clefts, each of which leads into a kind of flattened pouch, 



