V6 NOTES ON TASMANIAN CRUSTACEA, ETC. 



Mgs. 3 & 4. Mandibles, xo6. 



5. First maxilla, xl25. 



6. Second raaxilla, xl25. 



7. Maxilliped, x56. 



8. First guathopod, x56. 



9. Second pereiopod, x26. 



10. Third do. x26. 



11. Two last uropods and telson, x56. 



12. Last uropod, showing the inner branch (i.b.), xl25. 



13. Telson, from above, x56. 



Phreatoicus australis. Chilton. 



JPost Scri^ptum. 



In putting aside my specimens, described in this paper, fl 

 found in the tube containing Niphargiis montanus, collected by 

 Mr. Rodway, a siogle immature specimen of the remarkable 

 Isopod, Fhreatoicus australis. The specimen was only about 

 4 mm. (a little over ^ inch) in length. The occurrence of this 

 species adds another to the singular group of forms found in 

 the pools on the top of Mt. Wellington. The genus was 

 established in 1882 by Mr. C. Chilton, for the reception of a 

 bliod subterranean Isopod — P. typicvs — which occurs in wells 

 in Canterbury, New Zealand. In 1889, Mr. Chilton received 

 a small collection of Australian Crustacea, and this included a 

 new species of Phreatoicus (P. australis) from Mt. Kosciusko, 

 at a height of 5,700 feet. < 



I have already pointed out that the characters of Anaspis, 

 possessing, as it does, an extremely generalised structure, lead 

 to the conclusion that it is of great antiquity. The same 

 evidence is borne by the occurrence of Niphargus monianus. 



The evidence of the antique character of this fresh-water 

 fauna is still further strengthened by Phreatoicus. The dis- 

 tribution of the genus is, in the first place, remarkable, one 

 "blind species occurring in New Zealand, and another possessing 

 well-developed eyes, in two such widely separated localities as 

 Mt. Wellington (4,100ft.), in Tasmania, and Mt. Kosciusko 

 (5,700ft.), in south-eastern Australia. And, again, Phreatoicus 

 is a highly generalised Isopod, resembling the J seZZ2{?<2 perhaps 

 more than any other family, but sufficiently distinct to be 

 separated as the type of a new family, the Phreatoicidce. 



Probably an examination of other streams and pools at high 

 elevations in Tasmania and Australia will reveal further 

 examples of this interesting archaic fresh-water fauna. 



