Thanks SPW for his history of Aptychus, which makes A. D. d’Orbigny’s view [that it is a cirripede] improbable. [See Fossil Cirripedia 1: 3.]

Specimens SPW sent are very useful and interesting.

Thanks JWF and G. R. Waterhouse for cirripede specimens.

Cirripede fossil specimens returned.

Asks for reference to article by Kölliker, ["Some observations on the structure of two new species of Hectocotyle", Trans. Linn. Soc. Lond. 22 (1851): 9–22]. Asks for information.

CD expresses his inability to accept the view that the Hippuritidae are in any way a connecting link between the oysters and the barnacles.

Thanks for Supplement to SPW’s Manual of the Mollusca [1851–6]. Praises SPW’s work. "What an amount of labour is condensed in your little volume! … I fully believe & hope that you will reap the only reward worth having, the consciousness that you have done good service to the cause of Science."

Thanks for answer to query. "I see … that there is no hope of comparing the same genus at two different periods, and seeing whether the tendency to vary is greater at one period in such genus than at another period."

Inclined to dispute SPW’s doctrine that islands are generally ancient. Doubts that they are remnants of continents.

Comments on SPW’s book [Manual of Mollusca (1851–6)].

Mentions questions he has for SPW [see 1890].

Queries from CD on the distribution of molluscan genera referring to SPW’s Manual of the Mollusca [pt 3 (1856)], with SPW’s answers.

Thanks for information about variability in shells.

Comments on Harvey’s Seaside book [1849].

"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".