Fahrenheit, Celsius, and Réaumur, is introduced for comparison.
My various sources of information, and the friendly assistance I have received on all hands during the progress of our work, are acknowledged, so far as possible, in the text. I need here only renew my thanks to Staff-Commander May and the officers of the 'Lightning,' and Captain Calver and the officers of the 'Porcupine,' without whose hearty sympathy and co-operation our task could never have been satisfactorily accomplished; to my colleagues, Dr. Carpenter, F.R.S., and Mr. Gwyn Jeffreys, F.R.S., who have cordially assisted me in every way in their power; and to the naturalists into whose hands the animals of various classes were placed for description and study,—the Rev. A. Merle Norman, Professor Kölliker. Dr. Carter, F.R.S., Dr. Allman, F.R.S., Professor Martin Dunean, F.R.S.,
