396 POPULAR SCIENCE MONTHLY. 



on all continents, as well as islands ; they must have all descended from 

 one ancient progenitor, including the gigantic tortoise of the Himalaya. 



I think you must be cautious in not running the convenient doc- 

 trine that only one species out of very many ever varies. Eeflect on 

 such cases as the fauna and flora of Europe, North America, and 

 Japan, which are so similar, and yet which have a great majority of 

 their species either specifically distinct, or forming well-marked races. 

 We must in such cases incline to the belief that a multitude of species 

 were once identically the same in all the three countries when under 

 a warmer climate and more in connection; and have varied in all the 

 three countries. I am inclined to believe that almost every species 

 (as we see with nearly all our domestic productions) varies suffi- 

 ciently for Natural Selection to pick out and accumulate new specific 

 differences, under new organic and inorganic conditions of life, when- 

 ever a place is open in the polity of nature. But looking to a long 

 lapse of time and to the whole world, or to large parts of the 

 world, I believe only one or a few species of each large genus ulti- 

 mately becomes victorious, and leaves modified descendants. To give 

 an imaginary instance: the jay has become modified in the three 

 countries into (I believe) three or four species; but the jay genus is 

 not, apparently, so dominant a group as the crows; and in the long 

 run probably all the jays will be exterminated and be replaced perhaps 

 by some modified crows. 



I merely give this illustration to show what seems to me probable. 



But oh ! what work there is before we shall understand the geneal- 

 ogy of organic beings! 



With respect to the Apteryx, I know not enough of anatomy; but 

 ask Dr. F. whether the clavicle, etc., do not give attachment to some 

 of the muscles of respiration. If my views are at all correct, the 

 wing of the Apteryx cannot be (p. 452 of the Origin) a nascent organ, 

 as these wings are useless. I dare not trust to memory, but I know I 

 found the whole sternum always reduced in size in all the fancy and 

 confined pigeons relatively to the same bones in the wild Eock-pigeon: 

 the keel was generally still further reduced relatively to the reduced 

 length of the sternum ; but in some breeds it was in a most anomalous 

 manner more prominent. I have got a lot of facts on the reduction 

 of the organs of flight in the pigeon, which took me weeks to work 

 out, and which Huxley thought curious. 



I am utterly ashamed, and groan over my handwriting. It was 

 'Natural Preservation.' Natural persecution is what the author 

 ought to suffer. It rejoices me that you do not object to the term. 

 Hooker made the same remark that it ought to have been 'Variation 

 and Natural Selection.' Yet with domestic productions, when selec- 



