BY GEO. M. THOMSON, F.L.S. 71 



tlie preceding pairs, inner brauch minute ; telson cleft half-way 

 to the base. 



Length of largest specimens 6 mm. (about j inch.) The 

 colour varies from whitish-yellowish to brown, probably, 

 according to the vegetation of the pools in which they occur. 

 The integument is quite smooth. 



The^irs^ antennce (fig. 2) are about as long as the cephalon 

 and two anterior segments of thorax; the first joint of the 

 peduncle is stout ; the second shorter and more slender ; the 

 third half as long, and not half as stout as the first ; the 

 flagellum is few (about 14-) jointed, and is somewhat longer 

 than the peduncle ; the secondary flagellum is very short 

 and two-jointed. 



The second antejincB are about half as long as the first ; the 

 peduncle only shows two joints, which are about two-thirds as 

 long as the peduncle of the first pair; flagellum, about 

 eight-jointed, shorter than peduncle ; both pairs of antenna? have 

 very few short hairs on them. 



The mandible-palp (figs. 3 and 4) is three-jointed ; the second 

 joint has only a few short setae on it ; the third, which is sub- 

 equal with it in length, is sparingly fringed with setas on its 

 lower margin and extremity. 



The first maxillae (fig. 5) end in six stout spines, which are 

 all, more or less, pectinately toothed on the inner edge ; the 

 palp is stout, two-jointed, and ends in five short spines ; the 

 inner plate is rounded at the end and bears two slender 

 terminal setae. 



The second maxillae (fig. 6) are very thin and foliaceous, each 

 plate ending in a number of slender setEe. 



The maxillipeds (fig 7) have the plates on the first joint 

 short, rounded, and bearing four blunt teeth and numerous setae 

 at the extremity ; the plates on the second joint are also rather 

 short and rounded ; the inner edge at the extremity carries five 

 short, blunt teeth, outside of which are five rather long and stout 

 spines ; the four-jointed palp has numerous setae on its inner 

 margin, while its third joint bears a small rounded tubercle. 



The gnathopoda (fig. 8) are sub-equal in size and form in 

 both sexes ; the side-plates are deeper than broad, are evenly 

 rounded, and carry a few fine setae on the lower margin ; the 

 straight bases has a few long, slender setae on the posterior 

 margin ; the meros is short ; the ischium still shorter, and 

 fringed with setae on its distal margin ; the carpus broadly tri- 

 angular, and carrying a few setae along its lower edge ; the 

 propodos is nearly square, its upper edge is slightly rounded, 

 and bears a few cilia ; the lower edge is rugose; the trans- 

 verse palm is fringed with minute teeth, and ends in two or 

 three stout spines. 



The pereiopoda (figs. 9 and 10) increase slightly in length to 



