William Thomas Calman

“ Most crabs live in the sea, and even the land-crabs, which are abundant in tropical countries, nearly all visit the sea occasionally and pass through their early stages in it. Many shore-crabs living between tide-marks are more or less amphibious, and the river-crab of southern Europe or Lenten crab (Potamon edule, better known as Thelphusa fluviatilis) is an example of the freshwater crabs which are abundant in most of the warmer regions of the world. ”

“ Sometimes an annelid worm lives inside the shell along with the hermit and often the outside is covered with zoophytes. In some species, as in the British Eupagurus prideauxi, a sea-anemone is constantly found attached to the shell, profiting by the active locomotion of the crab and probably sharing the crumbs of its food, while it affords its host protection by its stinging powers. ”

“ Walking or crawling is the usual mode of locomotion, and the peculiar sidelong gait familiar to most people in the common shore-crab, is characteristic of most members of the group. The crabs of the family Portunidae, and some others, swim with great dexterity by means of their flattened paddle-shaped feet. ”