BY. C. CHILTOK. 733 



question therefore arises — is Haloniscas a form that has always 

 lived in salt water or is it a terrestrial form that has become 

 re-adapted to aquatic life? To decide this question we natural- 

 ly examine its characters to see if any of them show the primi- 

 tive structure we would expect if it has always lived in the 

 water. But none of them give decisive evidence of this. The 

 terminal segment of the body is more fully developed than in 

 other Oniscidae and the uropods are more exserted but not more 

 so than in Ligia, Trichoniscus and other genera which live 

 almost or quite wholly on land. The pleopoda, as already 

 mentioned, do differ somewhat from those of other Oniscidae 

 but this may be due to secondary adaptation. The mouth parts, 

 antenna?, etc., agree so closely with those of the Oniscidae, one 

 of the most strictly terrestrial families, that it seems improb- 

 able that Haloniscus should differ from the other members in 

 never having taken to a life on land. 



This tentative conclusion may be confirmed or disproved by a 

 consideration of the origin of Lake Corangamite — is it a por- 

 tion of the ocean that has become separated from the rest or 

 is it of separate origin and its saltness due to other causes'? 

 For information on these points I applied to Professor W. N. 

 Benson of the University of Otago who repLied that in the 

 article on Lakes of the Commonwealth in the Commonwealth 

 Yearbook, No. 4, 1911, p. 73, Lake Corangamite is classed as 

 one of the "Lakes filling subsided areas which have resulted 

 from the adjustment of the surface to the new conditions fol- 

 lowing the transference of large quantities of rock from under- 

 ground to the surface in the form of lava flow (basalt)." It 

 is one of the "lakes in basalt plains." "Most of these have 

 no streams entering them." Professor Benson adds that the 

 maximum depth of the lake is 10 ft., its height above sea- 

 level 380 ft., and that the basalt in which the lake lies is of late 

 Tertiary age. 



It seems evident from the information thus kindly supplied 

 by Professor Benson that the Lake is not of marine origin and 

 this appears to be confirmed by the brief account of the plants 

 of Lake Corangamite given by Mr. A. D. Hardy,* for though 

 on its shores there occur Salicornia, Enteromorplia and other 

 halophytic plants there does not seem to be anything distinctly 



•Victorian Naturalist, Vol. xxxv., p. 28. 



