Ed. i. p. 352, vi. p. 500.
See also _Origin_, Ed. i. p. 393, vi. p. 547.

{380} <Note by the author.> Many authors. <See _Origin_, Ed. i. p.
394, vi. p. 547.>

{381} _Nutria_ is the Spanish for otter, and is now a synonym for
_Lutra_. The otter on the Atlantic coast is distinguished by minute
differences from the Pacific species. Both forms are said to take
to the sea. In fact the case presents no especial difficulties.

{382} In _Origin_, Ed. i. p. 394, vi. p. 548, bats are mentioned as
an explicable exception to this statement.

{383} This reference is doubtless to _Mydaus_, a badger-like animal
from the mountains of Java and Sumatra (Wallace, _Geographical
Distribution_, ii. p. 199). The instance does not occur in the
_Origin_ but the author remarks (_Origin_, Ed. i. p. 376, vi. p.
527) that cases, strictly analogous to the distribution of plants,
occur among terrestrial mammals.

{384} See _Origin_, Ed. i. p. 313, vi. p. 454.

_On the number of species, and of the classes to which they belong in
different regions._

The last fact in geographical distribution, which, as far as I can see,
in any way concerns the origin of species, relates to the absolute
number and nature of the organic beings inhabiting different tracts of
land. Although every species is admirably adapted (but not necessarily
better adapted than every other species, as we have seen in the great
increase of introduced species) to the country and station it frequents;
yet it has been shown that the entire difference between the species in
distant countries cannot possibly be explained by the difference of the
physical conditions of these countries. In the same manner, I believe,
neither the number of the species, nor the nature of the great classes
to which they belong, can possibly in all cases be explained by the
conditions of their country. New Zealand{385}, a linear island
stretching over about 700 miles of latitude, with forests, marshes,
plains and mountains reaching to the limits of eternal snow, has far
more diversified habitats than an equal area at the Cape of Good Hope;
and yet, I believe, at the Cape of Good Hope there are, of phanerogamic
plants, from five to ten times the number of species as in all New
Zealand. Why on the theory of absolute creations should this large and
diversified island only have from 400 to 500 (? Dieffenbach)
phanerogamic pla