382 MORE ABOUT WHALES 



each side well forward in the body (not near the tail) a 

 pair of isolated, unattached bony pieces, which are the 

 hip-bone and thigh-bone all that remains of the hind 

 limbs. The neck is so short that in many whales the 

 seven neck-bones, or "vertebrae," are all fused into one 

 solid piece not longer than a single ordinary vertebra, 

 and showing six grooves marking off the seven vertebrae 

 which have united into one. 



The head is more strangely altered than any other 

 part of the whale. The jaws are greatly elongated so 

 as to give a beak-like form in all but this region is 

 specially long and narrow in the " beaked whales " known 

 to zoologists by the name Ziphius, in which it consists of 

 a solid piece of ivory-like bone, which we find in a fossil 

 state in the bone-bed of the Suffolk Crag. Farther back 

 the bones of the face are suddenly widened in all whales 

 and porpoises, and in many these bones grow up into 

 enormous crests and ridges. The nostrils, instead of 

 being placed, as in other animals, at the free end of the 

 snout or beak, lie far back, so as to form the " blow-hole," 

 which is near the middle of the head. 



The circulation of the blood and the breathing of whales 

 (including in that term the smaller kinds known as 

 dolphins and porpoises) is still a matter which is not pro- 

 perly understood. When a Greenland whale is struck by 

 the harpoon it dives vertically downward to a depth of 

 400 fathoms and more (nearly half a mile), and occasion- 

 ally wounds the skin and bones of its snout by violently 

 striking it on the sea-bottom. It remains below as long 

 as forty minutes. Physiologists wish to know how the 

 sudden compression of the air in the lungs in plunging to 

 this depth and the equally sudden expansion of it in 

 rising from such a depth is dealt with in the whale's 

 economy, so as to prevent the absolutely deadly results 

 which would ensue were any ordinary air-breathing animal 



