CLASSIFICATION OF ANIMALS. 
237 
as follows : — " Yektebral animals, having backbones : Avek 
TEBRAL ANIMALS, destitute of backboncs. Yeetebral animals 
are divided into, 1. Quadrupeds ; — the science of which has no 
popular name ; it includes four-footed animals, as ox, dog, 
mouse. 2. Birds ; — -the science of which is called ornithology ; 
it includes the feathered tribe, as pigeon, goose, wren. 3. Airif 
phihious Animals ; — the science of which is called amphihiolo- 
gy ; it includes those cold-blooded animals Avhich are capable 
of living on dry land, or in the water, as tortoise, lizard, serpent, 
frog. 4. Fishes ; — the science of which is called icJithyology ; 
it includes all aquatic animals w^hich have gills and fins ; as 
shad, trout, sturgeon, eel. Avertebral animals are divided 
into, 5. Insects ; — the science of which is called entomology / it 
includes all animals with jointed bodies, which have jointed 
limbs, as flies, spiders, lobsters. 6. Vermes; — the science of 
which is called helminthology ; it includes all soft animals of 
the avertebral division, which have no jointed limbs, with or 
without hard coverings, as angle-worms, snails, oysters, polypi, 
and infusory animals." 
377. Zoophytes^ or animal plants, bring us to the lowest beings 
in the animal kingdom. Some of the orders of this class con- 
tain animals which have neither heart, brains, nerves, nor any 
apparent means of breathing. These are sometimes called a^ii- 
mat plants ; many of them, as the corals^ are fixed to rocks, 
and change place. The term coral includes under it many spe- 
cies ; the red coral used for ornaments is the most beautiful. 
The substance of coral, when subjected to chemical analysis is 
found to consist chiefly of carbonate of lime ; the hard crust 
which envelops the animal substance is an excretion formed by 
it in the same way as the shells of the oyster and lobster are 
produced, or as nails grow upon the fingers and toes of the hu- 
man body. The quantity of this carbonate of lime elaborated 
by the little coral animal is truly wonderful ; islands are formed, 
and harbors blocked up by it. Fig. 165, a^ represents a branch- 
ing coral ; the dots show the apertures by which the animal re- 
ceives its nourishment. Some of the zoophytes are fixed by a 
kind of root to the bottom of the sea ; some, as the sea-nettle^ 
which appears like the segment of a circle, are carried about by 
the motion of the waters, without any voluntary motion, as are 
also the seordaisy^ sea-marigold^ and the sea-carnation^ so named 
from an apparent resemblance to those plants. We find here 
the sea-foM^ the sea-pen^ and the madrepore^ the latter of which 
are often thrown together in vast quantities. 
378. The sponge also belongs to this class of animal sub- 
376. Division of unimalsinto two classes — How many classes of Vertebral animals ? — How are Aver- 
tetwal animals divided ?— 377. Description of zoophytes— Corals— Various kinds of zoophytes.— 37^ 
Bponj;e. 
