218 



THE OPAL SEA 



equatorial belt, and yet are not fishes at all. 

 The whales, for instance, are popularly consid- 

 ered as fishes whereas they are warm-blooded 

 mammals. This is true of the porpoises, the 

 grampuses, the narwhals, the killers, the black 

 fishes. They are all cetaceans and live not in 

 the depths but on the surface. In form they 

 resemble the fislies, and have the fishes' tail 

 wherewith they propel themselves; moreover, 

 they are gregarious, traveling in schools for 

 great distances, following the chase like the 

 other sea rovers. But they are mammals, never- 

 theless. The whales are of many kinds and in 

 popular nomenclature are right whales, blue, 

 white, and gray whales, bowheads, hump-backs, 

 fin-backs, sulphur-bottoms. The larger ones 

 are toothless and live upon tiny crustaceans, 

 molluscs and jelly fish; others have rows of 

 teeth and feed upon squid, herring and mack- 

 erel. 



Taking them for all in all the cetaceans are 

 not a picturesque group. They are wonderfully 

 equipped for the consumption of small sea life 

 en masse (one rorqual perhaps swallowing thou- 

 sands of herring at a single gulp) and have 

 great adaptability to circumstance ; but in form 

 they are odd, though not clumsy, and in color 

 they are dull, sometimes quite dismally so. 



