18441858] CIRRIPEDES 97 



left in me; and this confession will make you think very Letter 50 

 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. 



To C. Lyell. Letter 51 



Nov. loth [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 Lepadida 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 Chthantalus * (a recent genus) from the 

 Chalk ! 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. 



To T. H. Huxley. Letter 52 



Down, July gth, 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 2 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) that I doubted it, for, differently 

 from my general habit, I have not extracted his grounds. It 



1 Chthamalus, a genus of Cirripedia. (A Monograph on the Sub- 

 class Cirripedia, by Charles Darwin, p. 447. London, 1854.) A fossil 

 species of this genus of Upper Cretaceous age was named by Bosquet 

 Chthamahis Darwini. See Origin, Ed. vi., p. 284 ; also Zittel, Traite 

 de Paleontologie^ Traduit par Dr. C. Barrois, Vol. II., p. 540, fig. 748. 

 Paris, 1887. 



2 This no doubt refers to A. Brulle's paper in the Cowptes rendus 

 1844, of which a translation is given in the Annals and Mag. of Natural 

 History, 1844, p. 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." 



7 



