OUR FRESHWATER ENTOMOSTRACA. 
53 
within their shells and close the valves, so that force and address 
seek in vain to open them.” We have selected one of the most 
common species to be found in the neighbourhood of London 
and elsewhere as our illustration, the Three-streaked Cypris 
( Cypris tristriata; figs. 18, 19). The shell itself with the 
animal withdrawn looks like a small bivalve shell (fig. 18), being 
of an oval form and somewhat kidney-shaped. It is of a green 
colour, and the hinder portion is marked with three narrow 
bands or streaks of a still deeper green. To see the enclosed 
animal, we must carefully break down the shell and dissect the 
body out. When carefully done, it appears like fig. 19. 
Such are some of the inhabitants of our fresh waters. It is 
difficult in a short space to do justice to them, for — 
Full Nature swarms with life ; one wondrous mass 
Of animals, or atoms organised. 
