46 DESCRIPTION OF A NEW SPECIES OP GALAXIAS, 



above the sea, and the rivulet takes its rise in a spring on its 

 summit, and forms, in its short course before it leaps into the 

 Grose YaUey, lying about 2,500 feet below, a series of small shady 

 cool pools, at different elevations, which are the abodes of this 

 fish. The species has never, I believe, been found in the Grose 

 River or any of the tributaries of the Nepean and Hawkesbury, 

 and I think we may safely take it for granted that it is not to be 

 found in them, as the Nepean and its tributaries were very closely 

 searched some years ago by Mr. Krefft, when investigating the 

 fresh water Fishes of Australia. 



The fall into the Grose Valley may probably be too precipitous 

 to admit of even the ova of the Fish reaching the river in safety, 

 but there is another mode of accounting for the absence of this 

 Fish in the lower portions of the stream in which they have been 

 found, and that is in the difference of temperatiu-e. The difference 

 between the shady pools on Mount Wilson and the exposed and 

 shallow pools of the Grose or Nepean Eivers must be immense, 

 and it may well be, that the Fish cannot survive the great 

 change of temperature. The genus Galaxias is in this respect 

 very remarkable. It is peculiar to the rivers flowing into the 

 Pacific south of the tropics, and apparently becomes more 

 abundant as the colder latitudes are reached. It is rare in the 

 rivers of New South Wales, more abundant in Victoria, stiU more 

 so in Tasmania and New Zealand, and is found in the rivers of 

 southern Chili, Magellan Straits, and the Falkland Islands. 



The species described up to the present time are as follows : — 

 G. alepidotus, Forst., Cuv. and Eichards=i^or5^^;-/, Guv. and Val. 

 New Zealand. 



,, truttaceus, Cuv. and Val., Eichards. Van Diemens Land. 



,, olidus, Gunth. ? Queensland. 



,, fasciatus, Gray, Cuv. and Val., Eichards, = Jro^^/iws and 

 reticulatus, Eichards. New Zealand and Auckland Islands. 



,, attenuatus, Jenyns, Cuv. and Val.,=.sc;r/3f^ and macidatus, 

 Eichards. New Zealand, Van Diemens' Land, Falkland 

 Islands and the Southern parts of Chili. 



