CASES OF ADAPTATION 137 



In confirmation of this view, a few cases have been recorded 

 in which nature has been caught, as it were, at work in the 

 actual formation of new species at the present time. The 

 first is that of the Porto Santo rabbits, carefully investigated 

 by Darwin. In the history of an early Spanish voyage it is 

 recorded that, a female rabbit having had a litter of young 

 on board, they were all turned loose on this small uninhabited 

 island near Madeira. This was about 1419, and from these 

 alone the island became fully stocked, and remains so still, 

 although the island is now fairly peopled. Darwin was able 

 to examine two of these rabbits preserved in spirits, three 

 others in brine, and two alive which had been in the Zoological 

 Gardens for four years. These seven specimens, though caught 

 at different times, closely resembled each other, they were all 

 full grown, yet they were very much smaller than English 

 wild rabbits, being little more than half the weight, and nearly 

 three inches less in length. Four skulls of the Porto Santo 

 rabbits diifered from those of English vdld rabbits in the supra- 

 orbital processes of the frontal bone being narrower; but they 

 differed considerably in colour, the upper surface being redder, 

 and the lower surface pale grey or lead colour instead of white ; 

 the upper surface of the tail, however, was reddish-brown in- 

 stead of blackish-grey as in all wild European rabbits, while 

 the tips of the ears had no black edging, as our rabbits always 

 have. 



We have here a very remarkable series of differences in size, 

 colour, and even in the form of the skull ; while it was noticed 

 at the Zoological Gardens that they were unusually wild and 

 active, and also more nocturnal in their habits than common 

 wild rabbits. In this case, these rabbits would certainlv have 

 been described as a distinct species if they had been found 

 in some more remote country to which it was certain that they 

 had not been introduced by man. 



Another example which shows nature at work, this time in 

 the actual process of " selection " of the better adapted indi- 

 viduals, occurred quite recently. In February 1898, at the 



