92 BRITISH ENTOMOSTRACA. 



has only three articulations, all of nearly equal length. 

 From the first and second a long filament is sent forth, 

 and three others spring from the extremity of the third. 

 These filaments are all beautifully plumose, and have a 

 joint at about the middle of their length.* The sixth 

 segment of the body has four projections issuing from it, 

 the first being prolonged, and bent upwards. 



The male is much smaller than the female. The su- 

 perior antennse are much larger, and spring from under 

 the beak, instead of from the beak itself. The inferior 

 extremities of the valves are more densely serrated than 

 in the female. It is comparatively rarely to be met with. 



Hah. — In almost all pools, and ditches of standing 

 water, round London, &c. ; common from April to 

 January. Belfast, May 1849, W. Thompson, Esq. 



2. Daphnia psittacea. Tab. IX. figs. 3, 4. 



Valves of shell, or carapace, oval, transparent, nearly 

 colourless. The head is large, somewhat square-shaped, 

 and the anterior part is beaked like the beak of a parrot. 

 The superior antennse are short, but larger than in pre- 

 ceding species, and rise from the under surface of the 

 beak. The posterior angle of the shell terminates in a 

 long, sharp point, which is closely serrated on both sides. 

 The margins of the valves are also closely serrated over 

 the greater part of their length, the serrae of dorsal margin 

 extending to near the commencement of the head. The 

 filaments of the antennse and abdominal lobe are finely 

 plumose. The eye is large. 



This species bears considerable resemblance to the 

 D. pulex, and at first sight may be easily confounded 

 with it. Upon close examination, however, the form of 

 the head, and the serrated dorsal margin, distinguish it 



* The number of the articulations, their relative size, and the number and 

 distribution of the filaments of these antenna;, arc the same in all the species 

 of the genus Daphnin. 



