VII FRESH-WATER MALACOSTRACA 2 I I 



In the Southern Hemisphere we have a species of Anaspides, 

 A. tasmaniae, occurring in mountain streams and tarns in 

 Tasmania, a related form whicli 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. Asdlus and Monolistra, 

 are confined to fresh water, others, such as SjAaeroma, 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 Xew 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, etc. 



The fresh -water Amphipoda all belong to the families 

 Talitridae, Gammaridae, and Haustoriidae (see p. 1.37). 



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. 



' Mem. Nat. Acad. WasMngton, iii., 1886, p. 1. 



