128 EXTINCT MONSTERS 



fishes ; the original land mammal from which whales are descended 

 has, in the course of time, become so fish-like in appearance 

 that even in these modern days there are some who yet speak 

 of them as fishes ! The shape of a whale is fish-like ; it has 

 lost its hind limbs through disuse; it has changed its fore 

 limbs into paddles, which have a certain fin-like aspect; and 

 its cousin, the porpoise, has developed a big triangular fin on the 

 back. To take another example : Pterodactyls are reptiles which 

 acquired the power of flight ; and some, at least, of them must 

 have borne a resemblance to modern bats. And yet pterodactyls 

 and bats are in no way related. The pterodactyl was a lizard 

 that could fly ; while the bat is a mammal that can do the 

 same. There is no question of relationship. Now let us apply 

 the same kind of reasoning to Dinosaurs and birds. For our 

 part, we confess to being not quite convinced. Dinosaurs walked, 

 ran, and perhaps some of the smaller ones even hopped on their 

 hind legs ; would it not follow as a matter of course that certain 

 rather bird-like developments would follow ? Let us reason the 

 matter out. For a horizontal body, like that of a lizard, to be 

 properly poised on two legs instead of four, the weight of the 

 viscera must be transferred backward, and the forward, or anterior 

 part of the body lightened. The lower bones of the region of 

 the hips (pelvis), with the contained organs, are thrown back- 

 ward, while the fore part of the body and the fore limbs are 

 lightened and much reduced in proportionate size. 



Changes such as these might be supposed capable of producing 

 those bird-like features in Dinosaurs which we have already 

 noticed, and on the strength of which some authorities believe 

 birds and Dinosaurs to have had a common ancestry. It may 

 perhaps be safer to look upon the ancestry of birds as one of 

 those problems that remain to be solved by some future 



