288 history or British Crustacea. 
occurs as a recent species living in the Gravesend ditches, 
where Mr. Pickering “ found it in great numbers, attached 
to the cases of caddis-worms, in a ditch which runs on the 
land side of the Thames bank, between Gravesend town and 
Coal-house Point, near an old mill ; the water flowing into, 
and not from the Thames, except at high tides.” 
Pam. CYTHERIDM 
Two pairs of antennae, the upper not furnished with the 
pencil of long filaments. Peet three pairs. 
Gen. 157. CYTHERE, Milller. 
Peet not enclosed in the shell, three pairs ; abdomen 
short. One eye. Carapace valves in front and behind, 
usually ornamented with a marginal series of fine spines. 
It is chiefly in sea- water that the species of this genus are to 
be found, especially in the little pools among rocks on the 
sea-shore. Dr. Baird observes, “ They live among the fuci 
and confervae, etc. which are to be found in such pools; and 
the naturalist may especially find them in abundance in those 
beautiful, clear, little round wells which are so frequently to 
be met with, hollowed out of the rocks of the sea-shore, 
