22 



THE POPULAR SCIENCE MONTHLY. 



seldom used for flight, would degenerate as time passed. The later 

 advent of man, in turn, has exterminated certain races of the wingless 

 birds such as the Dodo (Fig. 6) and Solitaire (Fig. 7) in Mauritius 

 and Rodriguez while the wingless and giant Dinornis of New Zealand 

 and its contemporaries have probably been hunted to the death of their 

 species by their human co-tenants of these strange lands. 



The ascent to the quadrupeds brings in review before us still more 

 striking illustrations of the apparently incomplete rendering of the 

 structures of animal life. No better instance of the " rudimentary or- 

 gans" of the naturalist can be found than in the group of the whales, 

 and more especially in the species from which we obtain the commercial 

 whalebone and oil the Greenland or right whale. This whale pos- 

 sesses no teeth in its adult state, but before birth teeth are found in the 

 gum. These teeth, however, are gradually absorbed, and utterly disap- 

 pear from the jaws, the adult whale possessing, as is well known, a great 

 double fringe of whalebone-plates depending from the palate. The 

 same remark holds good of the unborn young of ruminants, or animals 

 which " chew the cud" ; these animals in their adult state possessing 

 no front teeth in the upper jaw, but in their immature condition devel- 



Fig. 6. 



Fig. 7. 



oping these organs which, by the way, never cut the gum only to 

 lose them by a natural process of absorption. Now, here there can be 

 no question of use ; and certainly no adequate explanation of their 

 occurrence exists, save that which regards these fcetal teeth as the rem- 

 nants of structures once well developed in the ancestors of the whale- 

 bone whales and ruminants. To this supposition the evidence avow- 

 edly incomplete obtained from geology gives no contradiction, even 

 if it does not by any means supply the " missing links" in an adequate 

 fashion. We do know that among the oldest of the great leviathans 

 of the past was the Zeuglodon, which had teeth developed much in ex- 

 cess of anything we find represented in the dental arrangements of the 



