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.