WHALES 385 



many-jointed paddle of Ichthyosaurus and the other 

 allied marine extinct sea-dragons. In every curve of 

 the whale's body we seem to see an adaptation of 

 form to motion in water; even where we have, as in 

 the Sperm and Greenland Whales, a great blunt head 

 behind which the body tapers away, it can be shown 

 that, as in the not very differently shaped hull of an 

 old Dutch schooner, such a conformation is on lines 

 directly suited to speedy progress. 



While all the Cetacea are so far alike as to be very 

 easily distinguished from all other animals, yet there 

 are great differences between one whale and another ; 

 and not the least of these differences are in respect of 

 size. For some of the smaller dolphins are only about 

 a yard long, while many species of whales attain a 

 length of 50, 60, or 70 feet ; and the largest of all, the 

 Blue Whale, or Sibbald's Rorqual, is said to reach 

 100 feet in length, and examples of 85 feet are well 

 authenticated. We may make a rough estimate of 

 the weight of one of these gigantic creatures by remem- 

 bering the simple rule that in bodies of similar shape 

 the bulk or weight will vary as the cubes of the linear 

 dimensions. I find that a foetal Rorqual, just a foot 

 long, weighs 1 pound 6 ounces. It follows that a 

 whale of 40 feet long should weigh 40 3 , or 64,000 

 times as much as the said foetus, or somewhere about 

 38 tons ; a whale 85 feet long would, on the same pro- 

 portion, weigh close upon ten times as much, or some- 

 where about 370 tons ; and a whale 100 feet long would 

 weigh about 600 tons. 



The Cetacea at present existing are divided by 

 naturalists into two great groups — the Whalebone 

 Whales and the Toothed Whales, with which latter the 

 dolphins and porpoises are included. 



The Whalebone Whales are technically known as 



25 



