DAPHNIA. 269 



Gen. 140. DAPHNIA, Milller. 



Head produced downwards into a more or less prominent 

 beak. Upper antennae exceedingly small, one-jointed, and 

 situated under the beak ; lower antennse large and powerful. 

 The largest British species is not above -^ of an inch long. 



Daphnia pulex, Linn. sp. Branched Water-flea. (Plate 

 XYI. fig. 1.) — Carapace oval, transparent, dorsal margin 

 smooth ; lower extremity of the valves ending in a sharp 

 spine serrated on the edges. 



Hab. Pools and ditches of standing water. Common 

 from April to January. 



Daphnia psittacea, Baird. — Carapace oval, transparent; 

 head large, squarish, front part beaked like the beak of a 

 parrot ; dorsal margin of the carapace serrated. 



Hab. Pond on Blackheath (Dr. Baird). 



Daphnia Sch^efferi, Baird. — Carapace nearly circular, 

 surface finely reticulated ; head small. The largest British 

 species. 



Hab. Ponds, Bexley Heath, Kent ; and ponds, Norwood 

 Green, Surrey. 



Dr. Baird describes the motion of this species through 

 the water as being peculiar ; it is a tumbling, heavy sort 



