the antiquity
of four of them is so clearly shown.

I have got Harvey's seaside book, and liked it; I was not particularly
struck with it, but I will re-read the first and last chapters.

I am growing as bad as the worst about species, and hardly have a
vestige of belief in the permanence of species left in me; and this
confession will make you think very lightly of me, but I cannot help
it. Such has become my honest conviction, though the difficulties and
arguments against such heresy are certainly most weighty.

LETTER 51. TO C. LYELL. November 10th [1856].

I know you like all cases of negative geological evidence being upset.
I fancied that I was a most unwilling believer in negative evidence; but
yet such negative evidence did seem to me so strong that in my "Fossil
Lepadidae" I have stated, giving reasons, that I did not believe there
could have existed any sessile cirripedes during the Secondary ages.
Now, the other day Bosquet of Maestricht sends me a perfect drawing of a
perfect Chthamalus (a recent genus) from the Chalk! (51/1. Chthamalus,
a genus of Cirripedia. ("A Monograph on the Sub-class Cirripedia," by
Charles Darwin, page 447. London, 1854.) A fossil species of this genus
of Upper Cretaceous age was named by Bosquet Chthamalus Darwini. See
"Origin," Edition VI., page 284; also Zittel, "Traite de Paleontologie,"
Traduit par Dr. C. Barrois, Volume II., page 540, figure 748. Paris,
1887.) Indeed, it is stretching a point to make it specifically distinct
from our living British species. It is a genus not hitherto found in any
Tertiary bed.

LETTER 52. TO T.H. HUXLEY. Down, July 9th, 1857.

I am extremely much obliged to you for having so fully entered on my
point. I knew I was on unsafe ground, but it proves far unsafer than I
had thought. I had thought that Brulle (52/1. This no doubt refers to A.
Brulle's paper in the "Comptes rendus" 1844, of which a translation is
given in the "Annals and Mag. of Natural History," 1844, page 484. In
speaking of the development of the Articulata, the author says "that the
appendages are manifested at an earlier period of the existence of an
Articulate animal the more complex its degree of organisation, and vice
versa that they make their appearance the later, the fewer the number
of transformations which it has to undergo.") had a wider basis for his
generalisation, for I made the extract several years ago, and I
presume (I state it as some excuse for myself)