1908.] some other Fresh-water Crustacea from Tasmania. 471 
Pid. 5: Fig. 6. 
Fic. 5.—Paranaspides lacustris. Left mandible, inner view. end., endopodite of palp ; 
ex., exopodite. 
Fie. 6.—Paranaspides lacustris. First thoracic appendage. end., endopodite; ew., 
exopodite ; ep., epipodites ; lobe, additional lobe on ischiopodite. 
In all other essentials the structure agrees with that of Anaspides. 
Associated with Paranaspides lacustris in the Great Lake was a very 
abundant development of ground-living Crustacea, including several 
Amphipods (Neoniphargus and Chiltonia), and three or four apparently 
new species of the peculiar Australian and New Zealand genus Phreatoicus, 
curious Isopods of a very generalised nature. One of these species was a 
handsome spiny form with orange-coloured antenne and limbs, attaining 
about an inch in length. ! 
The extremely abundant development of this Crustacean fauna in the 
littoral zone of the Great Lake was very striking, and it seems probable that 
it furnishes an important part of the food for the imported English brown 
trout, which in this lake may attain to the enormous weight of 25 lbs. 
A dissection of the stomachs of several trout revealed the fact that they had 
been feeding upon these creatures. } 
The Anaspidacea and Phreatoicide of Southern Australia and Tasmania 
really standin much the same relation to other Crustacea as the Monotremata 
do to normal mammals, and it is of interest to enquire whence these peculiar, 
Crustacea have been derived, and how it comes about that they are now 
restricted to this isolated corner of the Antipodes. The most striking thing 
about their distribution at the present time is the fact that not only are they 
absolutely confined to the temperate parts of the Australasian region, but 
