58 THE WORLD OF THE SEA. 
the envelope breaks and allows these oviform particles to escape 
(fig. 9). These, like seeds, may remain for years before they find 
themselves in positions favourable for their development. When 
the surrounding circumstances are favourable, the germ begins to 
grow (figs. 10, 11). The infusore is formed (fig. 12), and grows 
rapidly (figs. 13, 14), and thus reaches its full development (fig. 15), 
and immediately sets out to find some other of its kind with which 
it may join its destiny and aid in the propagation of its species. 
Wonderful operations in a drop of water ! i 
Life is spread over nature in such well-nigh prodigal abundance 
that the smallest infusore has its parasite a little smaller, these 
INFUSORE AND ITS PARASITES. 
” 
serving in their turn as “dwellings and pasture grounds,” to use 
Humboldt’s expression, for other animalculz still less. The para- 
sites, a, of the Paramecium aurelia, b, are small creatures cylindrical 
in form, furnished with short suckers, swimming in the water 
by natatory cils. Sometimes they are spherical, and although 
wanting in cilia, yet they preserve their suckers. Swimming 
vigorously, they devote themselves to chasing the paramecium. 
Another of the parasites which also preys upon the paramecium 
remains perfectly quiet until one of them approaches, when it 
throws itself upon its victim and is carried along with it. It buries 
itself in the body, and in a short time multiplies to such a degree 
that sometimes fifty of them are found in a single individual ! 
