The Cambridge natural history, Vol. 03 (of 10)Note 41 — Chapter II · LAND AND FRESH-WATER MOLLUSCA, THEIR HABITS AND GENERAL ECONOMYReading editionSchumann, Schr. Ges. Danz. (2) vi. p. 159.◇Copy noteReturn to CHAPTER II LAND AND FRESH-WATER MOLLUSCA, THEIR HABITS AND GENERAL ECONOMY