Not only that but Darwin also wrote books on barnacles (a 2-volume
classic), coral reefs, orchids & other plants. Many of these are available
free thru the Gutenberg project. An alternate, easier to search, address
for Gutenberg:
http://www.thalasson.com/gtn/gtnletD.htm#letD

Aydin
home.earthlink.net/~aydinslibrary