Note R — Chapter IV · VARIATION AND NATURAL SELECTION.
Reading edition
Nature, vol. xli. p. 393. The variation in molluscs is often considerable. In one of the bays in the basement hall of the Natural History Museum is a series showing the variation in size, form, and sculpturing of Paludomus loricatus, which is found in the streams of Ceylon. These varieties have in former times been named as ten distinct species!