The specimen is not a fish but the larva of some batrachian or frog-like animal. Has sent it to British Museum, which says it resembles the axolotl of Mexico.

Has returned memorial to Chancellor of Exchequer; thanks CL for his note.

Lengthy remarks on cool period. Did not know of CL’s interest. New facts in new German and English [4th] editions of Origin will be too late for CL’s use. CD’s ten-year-old MS on cool period is available.

Thanks RC for photograph and for papers, which are of highest interest to CD. He is not fully convinced about the rose by RC’s graft-hybrid paper [Bull. Congr. Int. Bot. & Hortic. Amsterdam (1865): 65–80]. Still retains faith in his own view that no plant is perpetually self-fertilised.

Gives details of enclosed MS on cool period. Mentions Hooker’s opposed "axis of the earth" view. Causes of glacial period are beyond CD; "cannot believe change in land and water being more than a subsidiary agent".

Thanks for the paper on Sterrha (McLachlan 1865).

Writes on slave-making ants; cannot explain why fewer slaves are caught in England than in Switzerland.

Asks [Secretary] to list the proper titles of foreign societies of which he is an honorary member; he has mislaid diplomas.