82 A NATURALIST IN TASMANIA ch. 



zone, are a great quantity of Amphipods of two 

 or three species, some of which (e.g. Neoniphargus^ 

 Fig. 20) are closely related to freshwater European 

 species, while others (Chiltonia) are confined to the 

 southern hemisphere (see pp. 135, 136). I believe 

 that the above-mentioned Crustacea, so richly 

 developed both in point of variety of species and 

 in number of individuals, afford the chief food 

 for the Trout and account for the great size to 

 which these fish grow ; in several instances 

 I examined the contents of the stomachs of 

 freshly caught Trout, and in most cases they 

 were full of these Crustacea : moreover, it is 

 noticeable that the flesh of these Brown Trout is 

 almost always of a fine pink colour, and it is held 

 with considerable reason that this colour is due 

 to the decomposition products of the chitinous 

 shells of Crustacea. 



Of other invertebrata inhabiting the Great Lake, 

 perhaps the most conspicuous is a large fresh- 

 water Limpet ^ (Ancylus) sometimes measuring an 

 inch or more across, which is found sticking to 

 rocks below the water mark, while under the 

 stones a great quantity of dark olive Flat- worms 

 and a brown Leech {Glossophonia), which from its 

 affinities is probably a fish parasite, are found. 

 Very little is at present known about the fresh- 

 water worms of Tasmania, but a Sydney naturalist, 

 Mr. Goddard, with whom I made several expedi- 



^ This so-called Limpet is not related to the marine Limpets 

 but to the Land Pulmonates, e. g. the Snail {Helix). 



