Serial homologies in the Mollusca. Gives instances of repetition of homological parts in Radiata.

Has just finished Origin. CD has demonstrated a true cause for the production of species.

CD has loaded himself with unnecessary difficulty in adopting natura non facit saltum.

Murray has sold out Origin; wants a new edition immediately.

Asks THH to check whether Geoffroy de St Hilaire is correct [form of name].

Would be grateful for THH’s impressions on the truth of natural selection.

Sends enclosure [unspecified].

Reminds THH to mention [German] translation [of Origin] when he writes to R. A. von Kölliker.