PLANTS AND ANIMALS 73 
most abundant at or near the surface. Among these aquatic 
carnivores are certain small cousins (species of Addrovandia) of 
Venus’ Fly-Trap, which are specialized in much the same way. 
They are native to South and Central Europe, India, and Aus- 
tralia. 
The Bladderworts (species of U¢ricularia, fig. 1067) are widely- 
distributed ditch-plants, closely related to the Butterworts, and 
Fig. 1067.—Bladderworts ( Utricularia) 
represented in the British flora. They feed in part upon small 
aquatic organisms, and catch their prey in little bladder-like traps 
formed by modification of parts of the feathery leaves (fig. 1068). 
Each of these snares is not unlike a large water-flea in shape, 
and the resemblance is greatly increased by the presence of two 
branching bristles at the free end. Here, too, is placed the small 
opening into the bladder, guarded by a little transparent flap 
serving as a door, which opens inwards with the greatest ease, 
but prevents exit. Why little creatures should be attracted to 
