PLATE XXII

Atya scabra, A FRESH-WATER PRAWN OF THE FAMILY ATYIDÆ, WEST INDIES (REDUCED)

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The Brachyura (or Crabs) include many species that live in fresh water. Some of these, like the species of Sesarma (see [Plate XXIII].) and some other genera of the family Grapsidæ, are common throughout the tropics, passing up the rivers from the brackish water of estuaries, and being often found long distances inland in quite fresh water. The true River Crabs, however, belong to the family Potamonidæ, and are very common throughout the warmer regions of the globe. One species, Potamon edule ([Plate XXIII].), formerly called Telphusa fluviatilis, is found in the South of Europe (Italy, Greece, etc.). Very numerous species, as yet only imperfectly known, occur throughout the whole of Africa, in Southern Asia, and in the Malay Islands, extending to Australia in the south and Japan on the north. In the New World the River Crabs are found in South America, and extend north to Mexico and the West Indian Islands. Many of the River Crabs are amphibious in habits, and may be found burrowing in marshy ground or in damp forests. The young are hatched from the egg with all the appendages developed, and they remain clinging to the abdomen of the mother until after the first moult, when they are perfectly-formed little Crabs (see [Fig. 31], p. 78).

PLATE XXIII

THE RIVER-CRAB OF SOUTHERN EUROPE, Potamon edule (OR Telphusa fluviatilis) (REDUCED)

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