80 A NATURALIST IN TASMANIA ch. 



water, and this identical species is found in similar 

 situations at the extreme south of South America. 



It is, however, in the invertebrate fauna that 

 the Great Lake is particularly rich, and especially 

 so in the Crustacea. Mention has already been 

 made of the remarkable Mountain Shrimp of 

 Tasmania (Anaspides tasmaniae), which is found 

 at a high elevation on Mount Wellington and in 

 the clear tarns upon Mount Field, the Harz 

 Mountains, and on some of the mountains on 

 the west coast. I was fortunate to find in the 

 coastal waters of the Great Lake, especially in 

 weedy localities, an entirely new form of this 

 shrimp, which I have named Paranaspides lacu- 

 stris ; this shrimp, although it agrees rather closely 

 with Anaspides in its anatomy, is totally different 

 to look at, being of a transparent yellowish-green 

 colour, and with the body very much humped 

 in the middle : from its structure and observed 

 habits it evidently pursues more of a free swim- 

 ming, and less of a creeping habit than Anaspides, 

 This shrimp, which is apparently confined to the 

 Great Lake, is very abundant there. 



On the stones and among the weeds near the 

 shore of the lake I found great quantities of 

 a peculiar Crustacean genus called Phreatoicus 

 (Fig. 19), a genus confined to the Alpine regions 

 of southern Australia and New Zealand, and 

 belonging to a peculiar group of its own, agreeing 

 in its essential anatomy with the Isopoda, but 

 resembling in its external characters the other 



