54 DAEWINISM STATED BY DARWIN HIMSELF. 



sub-species, only two or three other species of rock-pigeons 

 are known, and these have not any of the characters of 

 the domestic breeds. Hence the supposed aboriginal 

 stocks must either still exist in the countries where they 

 were originally domesticated, and yet be unknown to or- 

 nithologists — and this, considering their size, habits, and 

 remarkable characters, seems improbable — or they must 

 have become extinct in the wild state. But birds breed- 

 ing on precipices, and good fliers, are unlikely to be ex- 

 terminated ; and the common rock-pigeon, which has the 

 same habits with the domestic breeds, has not been exter- 

 minated even on several of the smaller British islets, or 

 on the shores of the Mediterranean. Hence the supposed 

 extermination of so many species having similar habits 

 with the rock-pigeon seems a very rash assumption. More- 

 over, the several above-named domesticated breeds have 

 been transported to all parts of the world, and therefore 

 some of them must have been carried back again into 

 their native country; but not one has become wild or 

 feral, though the dovecot-pigeon, which is the rock-pigeon 

 in a very slightly altered state, has become feral in several 

 places. Again, all recent experience shows that it is diffi- 

 cult to get wild animals to breed freely under domestica- 

 tion ; yet, on the hypothesis of the multiple origin of our 

 pigeons, it must be assumed that at least seven or eight 

 species were so thoroughly domesticated in ancient times 

 by half -civilized man as to be quite prolific under confine- 

 ment. 



An argument of great weight, and applicable in sev- 

 eral other cases, is, that the above-specified breeds, though 

 agreeing generally with the wild rock-pigeon in constitu- 

 tion, habits, voice, coloring, and in most parts of their 

 structure, yet are certainly highly abnormal in other parts ; 

 we may look in vain through the whole great family of 



