| → this we find has been the case; 1859 1860 1861 1866 1869 | 
| they have been modified; 1872 | 
  | 
| → though very 1859 1860 1861 | 
| one with another, though 1866 1869 1872 | 
  | 
| → and some few are 1859 1860 | 
| and many are 1861 | 
| or sub-species, and some as certainly 1866 1869 | 
| or sub-species, and some as 1872 | 
  | 
| → species. 1859 1860 1861 | 
| each other on the several ranges. 1866 1869 1872 | 
  | 
| → illustrating what, as I believe, actually took place during the Glacial period, I 1859 1860 1861 1866 | 
| the foregoing illustration I have 1869 1872 | 
  | 
| → the 1859 1860 1861 1866 | 
| of our imaginary Glacial period, the 1869 1872 | 
  | 
| → the foregoing remarks on distribution apply not only to strictly arctic forms, but also to 1859 1860 1861 1866 | 
| it is necessary also to 1869 | 
| it is also necessary to assume that 1872 | 
  | 
| → for some of these are 1859 1860 1861 1866 1869 | 
| were 1872 | 
  | 
| → lower mountains and 1859 1860 1861 | 
| lower mountain-slopes and 1866 1869 | 
| world, for some of the species which now exist 1872 | 
  | 
| → plains 1859 1860 1861 1866 1869 | 
| lower mountain-slopes and on the plains 1872 | 
  | 
| → and 1859 1860 1861 1866 1869 | 
| are the same; and 1872 | 
  |