Note 8 — Chapter XXII · CAUSES OF VARIABILITY.
Reading edition
See Dr. Hooker’s Memoir on Arctic Plants in ‘Linn. Transact.,’ vol. xxiii. part ii. Mr. Woodward, and a higher authority cannot be quoted, speaks of the Arctic mollusca (in his ‘Rudimentary Treatise,’ 1856, p. 355) as remarkably subject to variation.