The creature appears to be confined to the deep pools of the rivers and tarns on the mountains of the southern and western portions of Tasmania.[92] The waters in which it occurs are always cold and absolutely clear, and there is no record of its living at altitudes much below 2000 feet, while it frequently occurs at 4000 feet. The body may attain upwards of two inches in length; it is deeply pigmented with black chromatophores, and it is held perfectly horizontal without any flexure. The animal rarely swims unless disturbed, usually walking about on stones and water-plants at the bottom of deep pools. In walking the endopodites of the thoracic limbs are chiefly instrumental, but they are assisted by the exopodites of the abdominal limbs. When frightened the shrimp can dart rapidly forwards or sideways by the strokes of its powerful tail-fan, but it never jumps backwards as do the other Malacostraca. It appears to browse upon the algal slime covering the rocks and on the submerged liver-worts and mosses, but it does not refuse animal food, even feeding on the dead bodies of members of its own species. The thoracic limbs, which are all biramous except the last pair, carry a double series of remarkable plate-like gills on their coxopodites. The slender and setose exopodites of the thoracic limbs are respiratory in function, being kept in continual motion even when the animal is at rest, and serving to keep up a current of fresh water round the gills. _Anaspides_ shows a remarkable combination of structural characters, some of which are peculiar, while others are possessed in common with the Peracarida or Eucarida. The chief peculiar characters are the entire absence of a carapace, and the freedom of the eight thoracic segments, with eight free thoracic ganglia in the nerve-cord; the peculiar double series of plate-like gills; the structure of the alimentary canal; and the fact that the eggs, instead of being carried in a brood-pouch, or affixed to the abdominal limbs, are deposited under stones and among water-plants.[93] [Illustration: FIG. 77.—_Anaspides tasmaniae_ in natural position for walking, × 1. The last two pereiopods point backwards and are overlapped by the first two pleopods. ] The Peracaridan features, uniting it especially with the Mysidacea, are the structure of the elongated heart, the filiform spermatozoa, and the fact that no complicated metamorphosis is passed through, the young hatching out in a condition similar to, though possibly not identical with, the adult form. The Eucaridan, especially Decapodan, features are the presence of an auditory sac on the basal joint of the antennules, and the modification of the endopodites of the first two abdominal appendages in the male to form a copulatory organ. A type of a new genus of this family was found by me in the littoral zone of the Great Lake of Tasmania at an elevation of 3700 feet, and named _Paranaspides lacustris_.