118 A Synopsis of the Recent British Ostracoda. 



All small species. Tlie first-named is of common occurrence ; 

 colour whitish, marked with two broad and conspicuous 

 transverse bands of black. The other two are somewhat rare ; 

 colour green. G. aculeata affects chiefly water that is slightly 

 brackish, and in such situations is sometimes accompanied by 

 Cypris salina. From the green colour of the animal, and 

 the contents of the digestive canal, it would appear that 

 it feeds upon the vegetation among which it is found, and 

 not upon animal matter, as seems to be the case with most 

 Crustacea. 



Paracypris, G. 0. Sars. — Upper antennae seven-jointed, 

 shortly setose ; lower antennse bearing, on the last joint but one, 

 a pear-shaped, pedicillated hyaline vesicle. Second pair of 

 jaws having a branchial appendage. Second pair of feet like 

 the first in form and size, pediform, five-jointed. Post-ab- 

 dominal rami large, clawed. Shell much higher in front than 

 behind. Habitat, marine. 



P. polita, G-. 0. Sars. — A very handsome species living in 

 water of considerable depth, and apparently of rare occurrence 

 in our seas, though ranging from the Channel Islands to Shet- 

 land and Norway. The remarkable vesicle attached to the 

 lower antennse is visible also in Pontocypris ; its use is entirely 

 unknown. 



jSTotodeomas, Lilljeborg. — Antennse like those of Cypris, 

 upper seven, lower six-jointed. Second pair of jaws without a 

 branchial appendage, pediform in the male. Post-abdominal 

 rami long and rather slender. Mucous gland and copulative 

 organs of the male very complex in structure. Shell of very 

 different shape in the male and female. Inhabiting fresh 

 water. 



N. monachus (Muller). — A tolerably common species, often 

 occurring in great abundance and at once recognizable by its 

 peculiarly quadrate form, flattened ventral surface and deep 

 black colour. 



Candona, Baird. — Like Cypris, except that the lower an- 

 tennse possess no tuft of setae and that the second pair of jaws 

 is destitute of a branchial appendage. Inhabits fresh water. 



G. albicans, Brady; fanciest, Baindi; compressa (Koch); Can- 

 dida (Muller); detecta (Muller). — These animals are unable to 

 swim, and are altogether sluggish in their movements, mostly 

 living on the muddy bottoms of ponds and stagnant water. 

 They are all whitish in colour, the shell surface polished, finely 

 punctated, or (as in C. compressa) delicately reticulated. 



Pontocypris, G. O. Sars. — Lower antenna bearing b vesicle, 

 as in Paracypris. Mandible and first pair of jaws having a 

 branchial appendage ; second pair of jaws without branchia, 

 palp large and subpedifonn, three-jointed, the last joint in the 



