22 INTRODUCTION 
foraminifers, and the pyramids of Egypt are built of nummulites, 
another genus of Foraminifera. It is estimated that an ounce 
of this deposit contains four millions of these protozoans, so it is 
impossible to conceive the numbers of once living animals repre- 
sented in the tombs of the Pharaohs. Telegraph-cables raised 
from the depth of two miles bring the message to naturalists 
that the bottom of the ocean at that depth is composed of little 
else than the calcareous shells of Foraninifera. 
Many of the lower animals resemble plantsin form. Hydroids 
and polyzoans are often gathered and preserved as seaweeds. 
Corals, sea-anemones, and holothurians are curiously like plants. 
For a time the confusion about the division of animals and plants 
was partly owing to this resemblance of forms, and the theory 
of the animal natnre of corals was for a long time considered to 
be refut iestimony of a naturalist who declared that he 
had set 1 bloom. Later this class of animals was 
believed to occupy an intermediate sphere and partake of the 
characteristics of both kingdoms. The name zodphyte, meaning 
“animal-plant” or “mingled life,” was adopted because of these 
resemblances and was formerly applied to these forms only. 
To-day it has a broader application. There is still a neutral class, 
called Protista, comprising organisms which have not yet been 
classified as plants or animals. 
