io6 Anintal Life and Intelligence. 



goat seem to be well authenticated. Of rats Darwin 

 says that "in some parts of London, especially near 

 the docks, where fresh rats are frequently imported, an 

 endless variety of intermediate forms may be found 

 between the brown, black, and snake rat, which are all 

 three usually ranked as distinct species." * Fertile hybrids 

 have been produced between the green-tinted Japanese and 

 the long-tailed Chinese pheasants. Mr. Thomas Moore, 

 of Fareham, in Hants, has been particularly successful in 

 producing a hybrid breed between the golden pheasant 

 (Thaumalia picta), whose habitat is Southern and South- 

 eastern China, and the Amherst pheasant (Thaumalia 

 amherstia), which is found in the mountains of Yunnan 

 and Thibet. In answer to my inquiries, Mr. Moore kindly 

 informs me that he "has bred the half-bred gold and 

 Amherst pheasant, crossed them again with gold, and re- 

 crossed them with half-bred Amherst, and kept on crossing 

 until only a strain of the gold pheasant remained. The 

 result is that the birds so produced are far handsomer than 

 either breed, since the feathers composing their tiplets as 

 well as those under the chin are of so beautiful a colour 

 that they beggar description. They all breed most freely, 

 and are much more vigorous than the pure gold or Amherst, 

 and their tails reach a length of over three feet. They are 

 also exceedingly prolific. Out of a batch of forty-two eggs, 

 forty chickens were hatched out, of which thirty-seven were 

 reared to perfection." 



Still, though there are exceptions, the general infertility 

 of allied species when crossed is a fact in strong contrast 

 with the marked fertility of varieties under domestication ; 

 concerning which, however, it should be noted that our 

 domesticated animals have been selected to a very large 

 extent on account of the freedom with which they breed 

 in confinement, and that domestication has probably a 

 tendency to increase fertility. The question, therefore, 

 arises Is the infertility between species, and the general 



* " Animals and Plants under Domestication," vol. ii. p. 65. For Darwin's 

 general conclusions on hybridism, see vol. ii. p. 162 of the same work. 



