376 
GEOGEAPHICAL DISTEIBUTION, 
Chap. XI. 
more lofty mountains, and on tlie temperate lowlands of 
the northern and southern hemispheres, are sometimes 
identically the same; but they are much oftener speci¬ 
fically distinct, though related to each other in a most 
remarkable manner. 
This brief abstract applies to plants alone: some 
strictly analogous facts could be given on the distribu¬ 
tion of terrestrial animals. In marine productions, • 
similar cases occur; as an example, I may quote a 
remark by the highest authority. Prof. Dana, that it 
is certainly a wonderful fact that New Zealand should 
have a closer resemblance in its Crustacea to Great 
Britain, its antipode, than to any other part of the 
w^orld.” Sir J. Eichardson, also, speaks of the re¬ 
appearance on the shores of New Zealand, Tasmania, 
&c., of northern forms of fish. Dr. Hooker informs 
me that twenty-five species of Alg 80 are common to 
New Zealand and to Europe, but have not been found 
in the intermediate tropical seas. 
It should be observed that the northern species and 
forms found in the southern parts of the southern hemi¬ 
sphere, and on the mountain-ranges of the intertropical 
regions, are not arctic, but belong to the northern tem¬ 
perate zones. As Mr. H. C. Watson has recently re¬ 
marked, ‘^In receding from polar towards equatorial 
latitudes, the Alpine or mountain floras really become 
less and less arctic.” Many of the forms living on the 
mountains of the warmer regions of the earth and in 
the southern hemisphere are of doubtful value, being 
ranked by some naturalists as specifically distinct, by 
others as varieties; but some are certainly identical, 
and many, though closely related to northern forms, 
must be ranked as distinct species. 
Now let us see what light can be thrown on the fore¬ 
going facts, on the belief, supported as it is by a large 
