IV.—Experiments and Observations on Crustacea: Part I. Immersion Experiments on Ligia

Descended from marine ancestors, Ligia oceanica, like other members of the sub-order (Oniscoidea or “slaters”) to which it belongs, has adopted a terrestrial mode of life. The other Oniscoidea have spread inland, invading regions far from the sea. Ligia, known as the sea-slater, is confined to the coastal fringe, and may possibly form a link between marine isopods and the more truly terrestrial forms.