126 Proceedings of the Royal Society of Victoria. 



Cephalon small, transversely suboblon^, subequal in length to 

 succeeding segments, antei'ior margin slightly obtusely produced in 

 the middle. Segments of peraeon with lateral margins evenly 

 rounded. Coxal plates inconspicuous — Caudal segment large, 

 subovoidal, longer than its greatest breadth, as long as the four 

 preceding segments combined, posterior margin between the 

 uropods slightly produced and evenly rounded. Eyes not formed. 

 Superior antennae not reaching to the end of the penultimate 

 peduncular joint of the inferior ones, flagellum composed of about 

 four joints. Inferior antennae exceeding the length of the body, 

 flagellum more than twice the length of the peduncle and com- 

 posed of about 38 articuli-; appendage outside third joint of 

 peduncle cylindriform, prominent. Legs slender, increasing in 

 length posteriorly. Operculum completely covering caudal 

 segment. Uropods narrow, long, subequal in length to caudal 

 segment, outer ramus small, about one-third the length of inner 

 ramus, inner ramus twice the length of peduncle. 



Male. — (Fig. 2) Body narrow — elliptical, narrowest anteriorly, 

 two and a quarter times longer than its greatest breadth. Caudal 

 segment very large, sub-spherical. Middle piece of operculum 

 with the end triangularly cleft mesially, and on each side of this 

 cleft margin slightly concave ; lateral distal angles slightly pro- 

 duced, bilobate. Similar in other respects of form to female. 



Colour — Pale ochreous, without markings. Spirit specimens 

 pale yellow. 



Lefigth — <? 3 mm. $3-5 mm. 



Habitat. — Fresh-water pool, Thorpdale, Victoria. 



Detailed Description. 



An external examination was made of eleven specimens com- 

 posed of males and females, and some of the latter had develop- 

 ing young in the marsupium. The largest female measured 3 "5 

 mm. and the largest male 3 mm. One of each sex was dissected, 

 which I shall now describe in some detail. 



Female. 

 Body (Fig. 1). — The body is oblong-oval in form, three times 

 as long as it is broad, and slightly narrowed both in front and 

 behind. The greatest breadth is at the third and fourth segments 



