32 G-. O. Sårs. 



rounded off, and without any trace of denticles. Head 

 strongly procumbent, terminating in a long and sharply 

 pointed rostrum. Surface of valves smooth, except in their 

 anterior part, where they are sculptured with 10 — 12 very 

 conspicuous, curved, transverse striæ, inferior edges densely 

 ciliated. Ocellus much smaller than the eye. Tail nearly 

 of uniform breadth, and obtusely truncated at the tip, 

 posterior edge somewhat flexuous, post-anal angle very slight, 

 ante- anal denticles extremely small, hair-like, terminal claws 

 strong and curved, each with 2 secondary denticles at the 

 base. Colour light corneous. Length of adult female 0,60 mm. 

 Remarks. — In a previous paper 1 ) I have wrongly 

 identified this species with Chydorus augustus of King, 

 which, as above stated, is identical with C. globosas, Baird. 

 The present form, which is a true Pleuroxus, is very closelv 

 allied to the European species P. aduncus, Jurine, and exhi- 

 hits a very similar sculpturing of the valves, but differs in 

 the more rounded form of the shell, and very markedly in 

 the rounding off of the infero-posteal corners of the valves, 

 where there is no trace of the denticles found here in all 

 the other known species of the genus. 



Description of the female. 



The length of adult specimens measures 0,60 mm., and 

 this form is accordingly of about the same size as the Euro- 

 pean species, P. aduncus. 



The shell is moderately tumid, and, seen laterally 

 (fig. 8), of a somewhat irregularly rounded form, the greatest 

 breadth being but little inferior to the length, and occurring 



x ) On a small collection of Fresh-water Entomostraca from Sydney 

 (Chr. Vid. Selsk. Forh. 1889) p. 5. 



