CRUSTACEA OF FRESH WATERS 173 



blance to a Woodlouse, with very long antennae, and 

 with a pair of long, slender, forked uropods project- 

 ing behind. The species is widely distributed in 

 Europe, and other species of the same and closely 

 related genera are found in North America. 



In Australia and New Zealand the Isopoda are 

 represented in fresh waters by a very peculiar group 



Fig. 60— A sellus aqmticits, Female, x 4. (After Sars.) 



of species, forming the suborder Phreatoicidea, 

 which have more the aspect of Amphipods than of 

 Isopods, since the body is more or less flattened 

 from side to side, instead of from above downwards. 

 With regard to the mode of distribution of the 

 fresh-water Isopoda, there is the same difficulty as 

 in the case of the Amphipoda, for the eggs are 



