and is surrounded with one or more rows of tentacala, which can be folded down 
into the aperture and concealed under the outer envelope. The interior of the body | 
is subdivided into a number of cells, which receive and distribute the food, and | 
contain the organs of propagation. The young are produced in a twofold manner, | 
from eggs and by budding. As most of the Polypi, with the exception of the soft, | 
leathery-skinned Actinia, secrete calcareous particles they gradually produce reefs of | 
rock or even islands. They are mostly very beautifully colored. — | 
Under the title of Protozoa are grouped together a multitude of organisations, 
mostly of microscopical minuteness and many of them of no definite shape, which | 
represent the lowest form of animal life. In their case but little can be said about | 
any distinct organs; their body consists rather of merely living matter, known as 
protoplasma, and which with but little change goes to form the substance of plants. 
Indeed the animal and vegetable world approach here so nearly together, that it is 
sometimes difficult to decide to which of the two to ascribe some of these forms of | 
“Shen Under the generic title of Protozoa are classed the Infusoria, Sponges and | 
izopoda. 
he Infusoria are for the most part exceedingly minute animalcules and are 
confined exclusively to the water, their bodies being in some cases furnished with cilia, 
and in others with flexible stems. Some species move about swiftly in the water, 
while others remain attached by the stem, and by moving to and fro create a motion | 
in the water and thus obtain their nourishment. Their propagation is effected either | 
by eggs or by spontaneous division, either longitudinal or transverse. — | 
The Sponges, Spongiw, are entirely vegetable formations, as far as appearance | 
is concerned. Their bodies, which are either lumpy, or bushy or resembling a cup 
in shape, grow and live under water, firmly attached to stones or to the bottom. 
Their skeleton is either simple, consisting of horny fibres, or compound, being 
strengthened by calcareous or siliceous spicula. The surface is perforated with a 
number of pores, into which the water enters and from which it is ejected after 
the nutriment has been extracted from it. Propagation is effected by means of eggs, 
which at first float freely in the water. — | 
Under the title of Rhizopoda are classed the very lowest forms of animal life. 
Their body consists of a gelatinous mass, sometimes enclosed in a shell, from the | 
aperture of which a number of minute filaments are protruded, which are used for 
the purposes of locomotion. They live in the sea, in the ooze, and are found at the | 
greatest depths, sometimes in amazing numbers. Their shells are found among the | 
sand of the seashore in every part of the world, while whole mountains are formed | 
of their fossil remains, and thus the humblest and most insignificant of living crea- 
tures perform their assigned part in the economy of nature and in fashioning or 
modifving the surface of the earth. 
+ ee 
