130 
SUPPLEMENT ON ANNELIDA. 
and stomach found in the blood-sucking leeches, but digestion 
is extremely slow in all. 
The leeches are essentially aquatic animals, most of them 
living in fresh water, but some in the sea ; a few occasionally 
quit the water, and as nature seldom acts on a single rule, one 
species is said never to go into it — humidity, however, is as 
necessary even to these as to the earth-worms. 
We have nothing to add on the genus Gordius, and proceed 
therefore to the translation of Cuvier’s description of such of 
the articulated animals as have articulated feet. 
