282 FOLLOW THE WHALE 



ing from the extreme fore end (in Mesoplodon mirus) to about 

 midway back on either side (in Mesoplodon densirostris). All these 

 whales are about twenty feet long, rather slender, and have pro- 

 nounced beaks. Their color seems to vary greatly; all but three are 

 known only from two or three specimens; and three come only from 

 the Southern Hemisphere. 



Cuvier's Whale, named after the famous French zoologist, has a 

 rostrum rather like that of a goose, flowing smoothly into the front 

 of the head, unlike most other ziphioids, which have pronounced 

 beaks and bulbous foreheads. It is apparently a fairly common spe- 

 cies and has been found all over the world. It grows to a length of 

 about thirty feet. 



Baird's Whale and its relative, Arnux's Whale, from the Southern 

 Hemisphere, are distinguished by having two, instead of one, pairs 

 of teeth at the front of their lower jaws, though those of the females, 

 as in most ziphioids, seldom show through the gums. Baird's species 

 reaches over forty feet in length; Arnux's only thirty. Both are black 

 above and white below, and they have very pronounced beaks. There 

 are distinct forms of Bottle-nosed Whales in the Northern Hemi- 

 sphere (Hyperoodon rostratus) and in the Southern Hemisphere 

 (Hyperoodon planifrons) . They are heavy-bodied animals, the males 

 reaching thirty-five feet in length, and the females twenty-five feet. 

 The young are about ten feet long when born. There is a pro- 

 nounced forehead which becomes more exaggerated in the males 

 with advancing age. This is supported by a forward-curving crest of 

 solid bone. The skulls of all ziphioids are bilaterally unsymmetrical, 

 which is to say that if you look down upon them, one side is quite 

 different from the other, as in the sperm whale. There is a small fin 

 far back on the body, the flippers are very small, and there is a single 

 crescentic blowhole. The tail flukes, looked at from above, have a 

 unique form among whales, having a convex hind edge instead of 

 being notched or concave as in all other species. Under the throat 

 there are two longitudinal grooves, or pleats, constructed like those 

 of the baleen whales. These animals also show other characteristics 

 that in some way appear to point towards the baleen whales; for in- 

 stance, the roof of the mouth is covered with large horny papillae 

 in rows which, being basically the same structure as the ridges on the 

 roof of our mouths, are fundamentally the same as the baleen plates 



