Art. XVII. — A New Genus of Phreatoicidae. 



By O. a. SAYCE. 



(AVith Plates XVIII., XIX.). 



[Eead 14th November, 1901.] 



Through the kindness of Professor W. A. Haswell, of Sydney, 

 I recently received a few specimens of a new blind Isopod of 

 the interesting and peculiarly Australian family Phreatoicidae. 

 They were lately received by him from Tasmania, and were 

 found in the burrows of the land crayfish Engaeus cunicularms. 



In all fundamental characters this new species agrees with 

 the genus Fhreatoiais, but has differences in degree sufficiently 

 marked to prohibit its inclusion in that genus ; nor can it be 

 considered congeneric with either of the other two genera of 

 this family ( Phreatoicopsis and Phreaioicoides), so that it is 

 necessary to establish another one to receive it. 



The family characters are defined by Dr. Chilton, of New 

 Zealand, as follows : — 



" Body subcylindrical, more or less laterally compressed. 

 Mandibles with a well developed appendage. Legs distinctly 

 divided into an anterior series of four and a posterior series of 

 three. Pleopoda broad and foliaceous and branchial in function, 

 but not protected by an operculum. Pleon large, of six distinct 

 segments. Uropoda, styliform." 



The representatives of the family ai-e mostly blind. Some 

 inhabit subterranean waters, others surface waters, often on the 

 summits of our Iiighest mountains, and one species beside the 

 present one is terrestrial. None are known of marine habit. 

 They appear to be a very ancient family, and structurally widely 

 separated from other known forms, and so far are only recorded 

 from Australia, Tasmania, and New Zealand. It would be of 

 interest to know if they exist in South America, for one is 

 justified in thinking tliat they might be found thei'e. 



