Words which were in italics in the original book are surrounded by
underlines (_italic_). Words which were originally printed in small
caps are in ALL CAPS. Obvious misprints have been fixed. Archaic and
unusual words, spellings and styling have been maintained when they
are used consistently. Spelling has been standardized within the book
where one spelling was predominant, even if it is not in common usage.
Inconsistent spelling and hyphenation has been maintained when there
was not a predominant spelling. Details of the changes follow.
No attempt has been made to correct the capitalization or standardize
the italicization of biological names--they are left as in the original.
All of Darwin's errata have been applied to the text, except the one on
page 255. It was not applied because the wording is not obvious.
This book was published in two volumes, of which this is the second.
The first volume was released as Project Gutenberg ebook #31558,
available at https://www.gutenberg.org/ebooks/31558.