reat class, I cannot doubt,
is one of the very highest ends of Natural History; and certainly most
interesting to the worker-out. Several of your remarks have interested
me: I am, however, surprised at what you say versus "anamorphism" (33/4.
The passage referred to is at page 63: "If, however, all Cephalous
Mollusks...be only modifications by excess or defect of the parts of
a definite archetype, then, I think, it follows as a necessary
consequence, that no anamorphism takes place in this group. There is
no progression from a lower to a higher type, but merely a more or
less complete evolution of one type." Huxley seems to use the term
anamorphism in a sense differing from that of some writers. Thus in
Jourdan's "Dictionnaire des Termes Usites dans les Sciences Naturelles,"
1834, it is defined as the production of an atypical form either by
arrest or excess of development.), I should have thought that the
archetype in imagination was always in some degree embryonic, and
therefore capable [of] and generally undergoing further development.

Is it not an extraordinary fact, the great difference in position of the
heart in different species of Cleodora? (33/5. A genus of Pteropods.) I
am a believer that when any part, usually constant, differs considerably
in different allied species that it will be found in some degree
variable within the limits of the same species. Thus, I should expect
that if great numbers of specimens of some of the species of Cleodora
had been examined with this object in view, the position of the heart in
some of the species would have been found variable. Can you aid me with
any analogous facts?

I am very much pleased to hear that you have not given up the idea of
noticing my cirripedial volume. All that I have seen since confirms
everything of any importance stated in that volume--more especially I
have been able rigorously to confirm in an anomalous species, by the
clearest evidence, that the actual cellular contents of the ovarian
tubes, by the gland-like action of a modified portion of the continuous
tube, passes into the cementing stuff: in fact cirripedes make glue out
of their own unformed eggs! (33/6. On Darwin's mistake in this point see
"Life and Letters," III., page 2.)

Pray believe me, Yours sincerely, C. DARWIN.

I told the above case to Milne Edwards, and I saw he did not place the
smallest belief in it.

LETTER 34. TO T.H. HUXLEY. Down, September 2nd, [1854].

My second vo