Transcriber's Notes.
The publisher's advertisement for the Contemporary Science Series, which was at the beginning of the book, was moved directly after the Index, before the other advertisements.
Spelling variants were there was no obvious preference were left as is. These include: "Ægean" and "Egean;" "bobac" and "bobak" (Arctomys); "boulder-clay" and "boulder clay;" "caspia" and "caspica" (Mysis); "earthworm" and "earth-worm;" "eocene" and "Eocene;" "europæus" and "Europæus" (Lepus); "freshwater" and "fresh-water;" "indistinguishable" and "undistinguishable;" "luscinea" and "luscinia" (Daulias); "maugei" and "Maugei" (Testacella); "Midwife" and "Mid-wife;" "miocene" and "Miocene;" "Miogale" and "Myogale;" "oligocene" and "Oligocene;" "paludosa" and "palludosa" (Branchinecta); "pensylvanica" and "pennsylvanica;" "Pica" and "Pika;" "pleistocene" and "Pleistocene;" "pliocene" and "Pliocene;" "polaki" and "Polaki" (Meles); "repeople" and "re-people;" "Rhodes" and "Rhodos;" "rusconii" and "Rusconii" (Molge); "souslik" and "suslik", along with derivatives; "subarctic" and "sub-arctic;" "subdivide" and "sub-divide", along with derivatives; "submarine" and "sub-marine;" "subtropical" and "sub-tropical;" "Tianshan" and "Tian Shan;" "woodlice" and "wood-lice", with "woodlouse" and "wood-louse."
Changed "Atlantis" to "Atlantic" on page 48: "across the Atlantic."
Changed "Millepede" to "Millipede" on page 115: "Millipede, Polydesmus gallicus."
Added period at end of sentence on page 144: "was more temperate."
Added period at end of sentence on page 145: "such northern latitudes."
Changed "know" to "known" on page 175: "known as the inter-glacial phase."
Changed "europea" to "europæa" on page 191: "Bullfinch (P. europæa)."