THE PROBLEM OF UTILITY. 493 



majority of species and, to use Mr. Eomanes' words, exist iu 

 " enormous numbers." The case of abnormal sports or mon- 

 strosities such as those here referred to can certainly not be 

 adduced as giving any support to this view. 



The next case, that o£ the Porto Santo rabbits, is held by 

 Mr. Eomanes to prove that the constant characters which dis- 

 tinguished them from common rabbits were only results of the 

 action of peculiar conditions on individuals, and were not produced 

 by natural selection. He arrives at this conclusion from the fact 

 that one of the two which died at the Zoological Gardens after 

 four years' captivity was sent to Darwin, who found that the 

 special colouring that distinguished the breed — the absence of 

 black on the tail and ear-tips and the reddish colour on the 

 back — had almost disappeared, and that the whole colouring was 

 very little different from that of the common wild rabbit. Hence 

 Mr. Eomanes concludes that other wild species may be really 

 only climatal forms, and their peculiar characters be non- 

 adaptive. But no mention is made of the remarkably small size 

 of these rabbits, which were only about half the weight of the 

 common wild species and which looked no larger than average 

 rats. If this also were a result of the action on the individuals 

 of scanty food or a peculiar climate, it would have rapidly 

 disappeared with ample food at the Zoological Grardens ; and 

 neither in this point nor in the peculiar form of the posterior 

 end of the skull and interparietal bone, which was so distinct 

 that Darwin figured it (see ' Animals and Plants under Domesti- 

 cation,' i. p. 118), did he note any difference in the dead animal. 

 It seems probable, therefore, that the colour-peculiarities of the 

 Porto Santo rabbits were due to a change of tint of the longer 

 hairs which may have been lost during the illness which led to 

 the animal's death. And as we have no information as to the 

 supposed change having been progressive during the four years 

 of confinement, or that it affected the second specimen, no such 

 conclusion as that drawn by Mr. Eomanes can be held to be 

 established. 



The only other case of much importance is that of changes of 

 colour said to be directly caused by changes of climate, and 

 especially by darkness in cave-animals. In this latter case it is 

 declared by Mr. Eomanes that the loss of colour cannot be of 

 any use and cannot have been caused by natural selection. It 

 is, therefore, an example of a useless character occurring in all 

 the individuals of many unconnected species. In the case of the 



