Origin of Species Variorum

→ OMIT 1869 1872

(however they may have become so), 1859 1860 1861 1866

→ seasons, 1859 1860 1861 1866 1869

nature of the seasons, 1872

→ If I am right in believing that 1859 1860 1861 1866 1869

As 1872

→ that 1859 1860 1861 1866 1869

in such a manner that 1872

→ take 1869 1872

in imagination adapt 1859 1860 1861 1866

that the range of the inhabitants of any country by no means exclusively depends on insensibly changing physical conditions, but in

a large

large

part on the presence of other species, on which it

depends,

lives,

or by which it is destroyed, or with which it comes into competition; and as these species are already defined

objects

objects,

→OMIT not blending one into another by insensible gradations, the range of any one species, depending as it does on the range of others, will tend to be sharply defined. Moreover, each species on the confines of its range, where it exists in lessened numbers,

will,

will

during fluctuations in the number of its enemies or of its prey, or in the →seasons, be extremely liable to utter extermination; and thus its geographical range will come to be still more sharply defined.

→If I am right in believing that allied or representative species, when inhabiting a continuous area, are generally

distributed →that each has a wide range, with a comparatively narrow neutral territory between them, in which they become rather suddenly rarer and rarer; then, as varieties do not essentially differ from species, the same rule will probably apply to both; and if we →take a varying species

inhabiting

a very large area, we shall have to adapt two varieties to two large areas, and a third variety to a narrow intermediate zone. The intermediate variety, consequently, will exist in lesser numbers from inhabiting a narrow and lesser area; and practically, as far as I can make out, this rule holds good with varieties in a state of nature. I have met with striking instances of the rule in the case of varieties intermediate between well-marked varieties in the genus Balanus. And it would appear from information given me by Mr. Watson, Dr. Asa Gray, and Mr. Wollaston, that

generally

generally,

when varieties intermediate between two other forms occur, they are