utes a species."

On page 91, in speaking of the idea that the species which make up a
genus may have descended from a common form, he says:--

"There must, indeed, be some principle on which the phenomena of
resemblance, as well as those of diversity, may be explained; and the
reference of several forms to a common type seems calculated to suggest
the idea of some original affinity; but, as this is merely a conjecture,
it must be kept out of sight when our inquiries respect matters of fact
only."

This view is again given in Volume II., page 569, where he asks whether
we should believe that "at the first production of a genus, when it
first grew into existence, some slight modification in the productive
causes stamped it originally with all these specific diversities? Or is
it most probable that the modification was subsequent to its origin, and
that the genus at its first creation was one and uniform, and afterwards
became diversified by the influence of external agents?" He concludes
that "the former of these suppositions is the conclusion to which we are
led by all that can be ascertained respecting the limits of species,
and the extent of variation under the influence of causes at present
existing and operating."

In spite of the fact that Prichard did not carry his ideas to their
logical conclusion, it may perhaps excite surprise that Mr. Darwin
should have spoken of him as absolutely on the side of immutability.

We believe it to be partly accounted for (as Poulton suggests) by the
fact that Mr. Darwin possessed only the third edition (1836 and 1837)
and the fourth edition (1841-51). (14/7. The edition of 1841-51 consists
of reprints of the third edition and three additional volumes of various
dates. Volumes I. and II. are described in the title-page as the fourth
edition; Volumes III. and IV. as the third edition, and Volume V. has
no edition marked in the title.) In neither of these is the evolutionary
point of view so strong as in the second edition.

We have gone through all the passages marked by Mr. Darwin for future
reference in the third and fourth editions, and have been only able to
find the following, which occurs in the third edition (Volume I., 1836,
page 242) (14/8. There is also (ed. 1837, Volume II., page 344) a vague
reference to Natural Selection, of which the last sentence is enclosed
in pencil in inverted commas, as though Mr. Darwin had intended to
quote it: "In other parts of Africa th