400 ORIGIN OF SPECIES 



is also obvious that the individuals of the same species, 

 though now inhabiting distant and isolated regions, must have 

 proceeded from one spot, where their parents were first pro- 

 duced : for, as has been explained, it is incredible that indi- 

 viduals identically the same should have been produced from 

 parents specifically distinct. 



Single Centres of supposed Creation. — We are thus 

 brought to the question which has been largely discussed by 

 naturalists, namely, whether species have been created at 

 one or more points of the earth's surface. Undoubtedly 

 there are many cases of extreme difficulty in understanding 

 how the same species could possibly have migrated from 

 some one point to the several distant and isolated points, 

 where now found. Nevertheless the simplicity of the view 

 that each species was first produced within a single region 

 captivates the mind. He who rejects it, rejects the vera 

 causa of ordinary generation with subsequent migration, and 

 calls in the agency of a miracle. It is universally admitted, 

 that in most cases the area inhabited by a species is con- 

 tinuous ; and that when a plant or animal inhabits two points 

 so distant from each other, or with an interval of such a 

 nature, that the space could not have been easily passed over 

 by migration, the fact is given as something remarkable and 

 exceptional. The incapacity of migrating across a wide sea 

 is more clear in the case of terrestrial mammals than perhaps 

 with any other organic beings; and, accordingly, we find no 

 inexplicable instances of the same mammals inhabiting dis- 

 tant points of the world. No geologist feels any difficulty in 

 Great Britain possessing the same quadrupeds with the rest 

 of Europe, for they were no doubt once united. But if the 

 same species can be produced at two separate points, why do 

 we not find a single mammal common to Europe and Aus- 

 tralia or South America? The conditions of life are nearly 

 the same, so that a multitude of European animals and plants 

 have become naturalised in America and Australia; and 

 some of the aboriginal plants are identically the same at 

 these distant points of the northern and southern hemi- 

 spheres. The answer, as I believe, is, that mammals have 

 not been able to migrate, whereas some plants, from their 

 varied means of dispersal, have migrated across the wide and 



