VII FRESH-WATER MALACOSTRACA 2) AI 
— 
In the Southern Hemisphere we have a species of Anaspides, 
A, tasmaniae, occurring in mountain streams and tarns in 
Tasmania, a related form which haunts the littoral zone of the 
Great Lake in Tasmania, and a small species, Koonunga cursor, 
occurs in a little stream near Melbourne. 
Of the Isopoda certain genera, viz. Asellus and Monolistra, 
are confined to fresh water, others, such as Sphaeroma, Idothea, 
Alitropus, and Cymothoa, have occasional fresh - water repre- 
sentatives. Packard! describes a remarkable blind Isopod, 
Caecidotea, from the Mammoth Cave of Kentucky, which occupies 
a very isolated position, and in the same work gives a very 
complete exposition of the cave-fauna of North America and 
Europe. 
The Phreatoicidae are a curious family of Isopods confined to 
the fresh waters of Australia and New Zealand, which bear a 
remarkable resemblance to Amphipods, being laterally com- 
pressed and possessing a subchelate hand on the anterior thoracic 
leg. These Isopods are exceedingly common in small mountain 
pools and in streams in Tasmania, and in the Great Lake in 
that country I have recently found a number of species which, 
together with some species of Amphipods, make up the dominant 
feature in the Crustacean fauna. One of these species may grow 
to fully an inch in length. The family is confined to the 
temperate regions, and is usually found on mountains. A 
number of species are known from the mainland of Australia, 
one coming from a high elevation on Mount Kosciusko, and 
another (Phreatoicopsis) from the forests of Gippsland attaining 
a great size, and living among damp leaves, ete. 
The fresh-water Amphipoda all belong to the families 
Talitridae, Gammaridae, and Haustoriidae (see p. 157). 
Among the Talitridae, or Sand-hoppers, Orchestia and Talitrus 
have marine as well as fresh-water and land representatives, while 
the American Hyalella is entirely from fresh water, most of the 
species being peculiar to Lake Titicaca. Many of these animals 
are partly emancipated from an aquatic life. Thus Orchestia 
gammarellus, which is common on the sea-shore of the Mediter- 
ranean, frequently penetrates far inland, and was found in large 
numbers by Kotschy near a spring 4000 feet up on Mount 
Olympus. 
1 Mem. Nat. Acad. Washington, iii., 1886, p. 1. 
