62 On Australian Entomostracans. 



posterior part of the dorsal edge, giving the shell the ap- 

 pearance of a heel; the valves are polished, of a transparent 

 greenish yellow colour, with a darker quadrangular mark 

 in the middle. 



In the females the ova seen through the shell give it a 

 heautiful scarlet colour towards the abdominal parts. The 

 males are generally darker and somewhat smaller. 



The thick setae on the branchial plate of the first pair of 

 foot jaws are plumose ; there is also a small branchial 

 plate on the second pair, which I do not find noticed ia Euro- 

 pean species. It also exists in Cypris Scottii (PI. X. C. a.) 

 The third (fourth of Baird) joint of the rami carries on 

 the inner side a remarkable short but stout and rather 

 clavate seta, which is moveable. I cannot conjecture its use. 

 It exists, I believe, in all the Australian species of Cypris. 

 The present species is very active in the day-time, and swims 

 very rapidly in an undulating line. Its habit is to swim 

 about from one mass of conferva to another, while each mass 

 seems alive with the multitudes moving about among its 

 tender threads. It is also a very social animal. Five or 

 six will often place themselves side by side among the con- 

 ferva touching each other, and remain in this position for 

 several minutes, as if enjoying each other's company. These 

 are generally females. 



Locality ; — Denham court, a large and very productive 

 pond in the flat, about a mile from the turnpike. 



2. Cypris Stoharti. PI. IX. B. 



The shell is oblong, and slightly sinuated on the posterior 

 dorsal margin. The valves are unequal, the left being the 

 larger. They are polished, and apparently of a yellowish 

 colour. I have seen but a single specimen, which I am 

 unwilling to destroy by dissection. I found it in a bottle 



