330 THE EFFECTS OF CONDITIONS 



had an influence on the hairy covering of animals. 

 Thus he says " Dr. Falconer states that the Thibet 

 mastiff and goat, when brought down from the Him- 

 alaya to Kashmir, lose their fine wool. At Angora not 

 only goats, but shepherd-dogs and cats, have fine fleecy 

 hair, and Mr. Ainsworth attributes the thickness of the 

 fleece to the severe winters, and its silky lustre to the 

 hot summers. Burnes states positively that the Kara- 

 kool sheep lose their peculiar black curled fleeces when 

 removed into any other country." 



What may be termed, perhaps, the classical instance 

 of the formation of a local race through changed con- 

 ditions of life, is that of the Porto Santo rabbit.* A 

 female rabbit and her young were turned loose on the 

 Island in 1418, and they increased so rapidly as to be- 

 come a nuisance, and finally caused the abandonment 

 of the settlement. The present-day form of these rab- 

 bits shows very considerable differences from the 

 original form. Thus the two measured by Darwin 

 were only 14 \ and 15 inches in length, instead of the 

 17 or 18 inches of the English rabbit. The weight 

 of one of them which had, however, become 

 somewhat thin from living in captivity was only 

 1 pound 9 ounces, four English wild rabbits averaging 

 3 pounds 5 ounces. The limb bones were smaller in 

 the proportion of rather less than five to nine. In 

 colour, the Porto Santo rabbits have a redder upper 

 surface, rarely interspersed with any black or black- 

 tipped hairs, and in none of the seven specimens exam- 

 ined by Darwin had the upper surface of the tail and 

 the tips of the ears any of the blackish gray fur which 

 * " Animals and Plants," i. p. 118. 



