384 THE INHABITANTS OF THE SEA. 
gression through the water and for drawing alimentary particles 
into the interior of their body. Though most of the Infusoria 
live in ponds, morasses, pools, wells, or cisterns, yet many are 
marine, as, for instance, the Curchesium polypinum, which is 
frequently found attached to corallines, and the Vaginicolu 
valvata, which from its sheath and valve strongly reminds one 
of a tubicolar annelide. 
Marine Infasoria. 
a. Vaginicola valvata, showing animal extended, and valve (¢) raised. 
a’, The same, showing animal contracted within its sheath, and valve (g’) shut down. 
b. Lagotia viridis, showing rotatory organ (2). 6’. Young animal of preceding. 
The wide diffusion both in time and space of the marine 
Protozoa, and chiefly of the Foraminifera and Polycystina, is 
a sufficient proof of their vast importance in the household of 
the seas. Along with the Diatoms and other microscopical 
forms of vegetation on which their own existence depends, they 
evidently constitute the basis on which the superstructure of all 
the higher orders of the animal life of the ocean reposes. 
Hosts of minute crustaceans, annelides, acalephze, and molluses, 
feed upon their inexhaustible legions, and serve in their turn to 
sustain creatures of a larger and still larger size until finally 
Man is enabled to feast on the abundance of the seas. 
