Among the small animalcules of the phylum /Protozoa/ are some which
are familiar to all by name, such as the /Infusoria/, which are
most interesting creatures to examine in a drop of water under
the microscope. A more tangible example of the /Protozoa/ are the
/Foraminifera/. /Foraminifera/, like diatoms, have a shell-like
covering, and these shells, among the most plentiful of which are
those of the genus /Globigerina/, fall, as do those of diatoms, in
immense numbers to the bottom of the ocean, and form respectively
what are known as /Globigerina/ and diatomaceous ooze. In course of
time the sedimentary strata become fossilized; thus, the stone of
which the city of Paris is built consists of fossilized [pg022]
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 represented
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 /Foraminifera/.
Many of the lower animals resemble plants in 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
nature of corals was for a long time considered to be refuted by
the testimony of a naturalist who declared that he had seen them
in bloom. Later this class of animals was believed to occupy an
intermediate sphere and partake of the characteristics of both
kingdoms. The name zoöphyte, 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.
[pg023]
V
DISTRIBUTION OF ANIMAL LIFE IN THE SEA
All living things which inhabit the sea have their appointed
boundaries, and the localization of marine life is as distinct as
is that of terrestrial life. Each kind of beach has forms of life
peculiar to itself. Those animals which inhabit rocky shores or stony
beaches or sand or mud may be looked for anywhere under similar
physical surroundings. They are, however, modified by climatic
conditions, and in wide ranges differ in genera and species. The
rocky coast of Maine has a class of sea-urchins and starfishes
which are different from those which live on the rocky shores of
the northern Pacific coast, yet they are all easily recognized as
belonging to the same family, and a description of typical forms is a
sufficient guide to the recognition of their relationships.
Public-domain text, read in full here on John Shaqi.
Reviews
Reviews
No reviews yet
Be the first to share your thoughts on this work.
Join the Discussion
Join the discussion
Sign in to leave a comment or review.
Sign InorCreate an account