268 THE INHABITANTS OF THE SEA. 
been driven into its gaping portals, it is presently crushed be- 
tween a pair of formidable sharp-toothed jaws, which are per- 
petually in motion, whether the animal is taking food or not. 
After having undergone the action of this lively apparatus, 
the aliment passes into a tubular stomach surrounded by a 
cushion-like mass of cells commonly coloured with the hue of 
the food, and, therefore, concluded to be connected with the 
digestive system. 
Conochilus volvox.—(Highly magnified.) 
a. Jaws and teeth. b. Papille. c. Glands. dd. Ovarium. 
The rotifera are either naked or covered with a sheath, and 
many inhabit a tube formed by themselves, attached by its 
lower end to some water-plant, and open at the summit, from 
which the animal protrudes when it would exercise its active 
instincts, and into which it retires for repose from Jabour or for 
refuge from alarm. The majority, however, have a fureated 
foot, which is often capable of contraction by a set of telescopic 
sheathings or false joints, and by which they are enabled to 
secure a hold of the minute stems of water-plants. This is 
