ON THE ANASPIDACEA, LIVING AND FOSSIL. 547 
They appear to be omnivorous, as they will feed upon the 
dead bodies of insect larve or even upon one another, but 
their chief food is the algal slime covering the rocks among 
which they live, and they also browse upon the submerged 
shoots of mosses and liverworts. 
The rivers and tarns in which they live are singularly free 
from any enemies such as predaceous fish which might prey 
upon them, the only fish inhabiting these highland waters 
being the little “ Mountain Trout,” Galaxias truttaceus. 
The English Trout, which have multiplied so wonderfully in 
the Tasmanian streams and lakes, have hardly penetrated to 
the mountain fastnesses where Anaspides dwells. 
The only parasite found infecting Anaspides isa peculiar 
species of neogamous gregarine which lives in the free state 
in the alimentary canal and forms large associated cysts in 
the liver-tubes, often in very great numbers. This gregarine 
will shortly be described in this journal by Mr. J. S. 
Huxiey. 
Paranaspides lacustris is known only from the speci- 
mens collected by me in the great Lake of Tasmania at an 
elevation of 3700 ft., where it inhabits the littoral region, 
living among the weeds and stones at a small depth rather 
after the manner of a prawn. 
Its markedly humped back and translucent green colour 
give it very much the appearance of a small prawn, e.g. 
Hippolyte, and it follows more of a swimming habit than 
Anaspides, but in other respects it resembles the latter 
closely. It doubtless falls an easy prey to the great quantities 
of large English brown trout which inhabit the lake, and it is 
probably in danger of an early extinction. 
Koonunga cursor has been found hitherto only in a 
small runnel issuing from the Mulluam Mullum Creek, 
Ringwood, to the west of Melbourne, and it is the only member 
of the living Anaspidacea which lives at a low level. In 
general appearance and habits it resembles Anaspides 
more closely than Paranaspides does, although it is morpho- 
logically very distinct. The specimens which Mr. Sayce 
