168 
BRITISH ENTOMOSTRACA. 
they may be seen to fall in gyrations to the bottom, with- 
out ever attempting to dart through the watery element, 
as is the case with the Cyprides. Upon reaching the 
bottom, they open their shells and creep along the surface 
of the glass ; but when touched or shook, they immediately 
again withdraw themselves within their shell, and remain 
motionless. This inability to swim is no doubt owing 
to the want of the pencils of long hairs or filaments which 
adorn the superior and inferior antennae of the Cyprides, 
and which we have already seen are the organs by means 
of which they swim. My opportunities for observing 
these tiny animals have been so limited, and the difficulty 
of keeping them alive, from the rapidity with which sea- 
water becomes putrid wfeen kept in a room in a small 
vessel, is so great, that I cannot make any additional 
statements respecting their economy or habits. The 
species, however, are undoubtedly numerous, and the 
labours of any inquirer after them would assuredly be 
rewarded with much success. 
1. Cythere flavida. Tab. XXI, figs. 12, 12^. 
Cytheue elavida, Muller , Entomost., 66, t, 7, f. 5, 6, 1781. 
— Latreille, Hist. Nat. Crust., iv, 253. 
— Besmarest , Consid. gen. et part. Crust., 388. 
— Bose , Man. d’Hist. Nat. Crust., ii, 284. 
— Baird, Mag. Zool. and Bot., ii, 142; Trans. 
Berw. Nat. Club, ii, 153. 
Monoctjlus flavldus, Gmelin , Linn. Syst. Nat., 3001, No. 33. 
— Fabricius, Ent. Syst., ii, 494. 
— Manuel, Enc. meth., vii, 725, t. 266, f. 10, 11. 
— Rees, Cyclopsed. art. Monoculus. 
Shell oblong, narrow, anterior extremity more acute 
than posterior; smooth, shining, of a pale yellow horn 
colour, and transparent. Inferior margin nearly straight ; 
superior arched. 
Hah. — Among Confervse in pools of sea- water at Cocks- 
burnspath, Berwickshire, 1835. In sand, from Torquay ; 
W. C. Williamson, Esq. - /iaA . /ftf. 
