cies is very common in its young state, but a great many must fall a prey to their many enemies, amongst the chief of which may be reckoned Neptunus pelagicus, as large ones are of rare occurrence. One that I have procured measures 10 centimetres across the carapace, but specimens of this size are seldom found. It has a wide distribution: East coast of Australia, New Zealand, Japan, and China.
Tribe Catametopa or Grapsoidea.
15. Macrophthalmus setosus (M.-Edw.).—This species is essentially a burrowing one, frequenting mud-flats. Its burrows, may be found here and there among those of Helæcius cordiformis (q.v.), but cannot be mistaken for the latter on account of the acute angle it makes with the surface, whereas the burrows of H. cordiformis are vertical and smaller. Colour yellowish brown, covered with setæ. Port Jackson, New South Wales. Common.
16. Helæcius cordiformis (Dana).—Found in similar situations to the preceding, but is much more common. The mud-flats, where these animals dwell, possess a most animated appearance, and remind the observer very forcibly of a busy city, of which the soldiers are Mycteris longicarpus (q.v.) and the civilians H. cordiformis (of which there are myriads), and all their little legs moving in concert make quite a great clatter. They are extremely amusing. On anyone approaching they show fight at once, holding up their comparatively large "nippers" as high as they can, so that as they retreat—which they do with their "faces to the foe"—they very often roll over backwards, so eager are they to show their weapons. The very rotund body is of a deep reddish brown colour. New South Wales, Tasmania.
17. Ocypoda cordimana (Desm.).—The Crabs of this genus are noted for their extreme swiftness of foot; indeed, they run so fast, and their colour assimilates so well with the sand, that they appear like pieces of cotton-wool or feathers being blown along by the wind. They are found wherever there is a good stretch of sandy beach, in which they make their burrows. These burrows average about 2 ft. in depth. East coast of Australia.
18. Grapsus variegatus (Latr.).—This is, without doubt, the dominant species of Crustacea in Australian waters, is distributed over a wide area, and presents great variation. They are found in great numbers all along the rocks at low tide, but scurry off
