AMPHIPODA AND ISOPODA FROM BARRINGTON TOPS. 91 



fairly numerous, and, just as in Europe and North America, 

 they include surface forms with eyes and blind subterranean 

 forms, both being sometimes found together in surface 

 streams. The difficulty of classifying these forms is already 

 considerable and will probably be greater when other 

 specimens from intermediate localities are examined, 

 though when a sufficient number of these are accurately 

 known, it will doubtless be possible to trace out the lines 

 upon which development has taken place. It seems likely 

 that they have arisen from a form that could be rightly 

 included in the genus Gammarus, and that is perhaps still 

 represented by G. australls Sayce. From this, there have 

 arisen forms resembling the genus Niphargus of Europe, 

 but it is clear that the development of these in Australia 

 has been independent of that in Europe, and that, as G. W. 

 Smith 1 has pointed out, we have here a case of convergence 

 that is well worthy of attentive study. The fresh water 

 Amphipoda of Australia have differentiated into genera and 

 species simulating those of Europe, much in the same way 

 as the marsupial mammals have differentiated into groups 

 parallel to those of the true mammals. 



Phreatoicus shephardi Sayce (figs. 13 to 17). 



Plireatoicus shephardi Sayce, Proc. Roy. Soc. Victoria, 

 vol. 13, p. 26, pi. 3. 



Of this species there were numerous specimens in the 

 collection. Mr. Hedley has been kind enough to give me 

 the following particulars as to the locality and circum- 

 stances under which they were taken. He says that they 

 came from a height of nearly 5,000 feet, at the source of 

 the river Manning, N.S.W., in South Latitude 32°, much 

 further north, therefore, than previous records of the 

 species. The surroundings were quite subalpine, near by 

 was a Fagus forest ; indeed, the spot is a subalpine island 

 in a subtropical area. The broad, shallow valleys of the 



1 G. W. Smith, loc. clt., p. 77. 



