18 ANIMAL LIFE 
one outside of the capsule. In the protoplasm inside of 
the capsule lies the nucleus or nuclei; and from the proto- 
plasm outside of the capsule rise the numerous fine, thread- 
like pseudopods which project through the apertures in the 
shell, and enable the animal to swim and to get food. 
Most of the myriads of the simplest animals which 
swarm in the surface waters of the ocean belong to a few 
kinds of these shell-bearing Globigerine and Radiolaria. 
Large areas of the bottom of the Atlantic Ocean are coy- 
ered with a slimy gray mud, often of great thickness, which 
is called globigerina-ooze, because it is made up chiefly of 
the microscopic shells of Globigerine. As death comes to 
the minute protoplasmic animals their hard shells sink 
slowly to the bottom, and accumulate in such vast quanti- 
ties as to form a thick layer on thé ocean floor. Nor is it 
only in present times and in the oceans we know that the 
Globigerine have flourished. All over the world there are 
thick rock strata which are composed chiefly of the fos- 
silized shells of these simplest animals. Where the strata 
are made up exclusively of these shells the rock is chalk. 
Thus are composed the great chalk cliffs of Kent, which 
gave to England the early name of Albion, and the chalk 
beds of France and Spain and Greece. The existence of 
these chalk strata means that where now is land, in earlier 
geologic times were oceans, and that in the oceans Globi- 
gerine lived in countless numbers. Dying, their shells 
accumulated to form thick layers on the sea bottom. In 
later geologic ages this sea bottom has been uplifted and 
is now land, far perhaps from any ocean. The chalk strata. 
of the plains of the United States, like those in Kansas, are 
more than a thousand miles from the sea, and yet they are 
mainly composed of the fossilized shells of marine Pro- 
tozoa. Indeed, we are acquainted with more than twice as 
many fossil species of Globigerine as species living at the 
present time. The ancestors of these Globigerinew, from 
which the present Globigerine differ but little, can be 
