| degree of mutual resemblance.” 
| served in insects and worms. 
' tem consists of two long cords, extending the 
| at intervals by various knots, or ganglions. 
ANIMAL. 
but the latter is very often found wanting. In 
only one family, however, there are exhibited the 
organs of hearing. We always find a complete 
circulating system, and particular organs for 
respiration. The functions of digestion and of 
secretion are performed in a manner very nearly 
as complicated as in the vertebrated animals. 
Animals possessed of this second form are called 
molluscous animals (Animalia mollusca) from the 
Latin, mollis, soft. Although the general plan 
adopted in the organization of their external 
parts is not so uniform as in the vertebrated ani- 
mals; yet, in so far as regards the internal struc- 
ture and functions, there is at least an equal 
The cuttle-fish, 
oyster, slug, and garden-snail, are familiar in- 
_ stances of this class of animals. 
3, AnricuLATA—A rticulated Animals. 
“The third form is that which may be ob- 
Their nervous sys- 
entire length of the intestinal canal, and dilated 
The 
first of these knots. placed upon the cesophagus 
or gullet, and called the brain, is scarcely larger 
than any of the others, which may be found ar- 
ranged along the intestinal canal. It communi- 
cates with the other ganglions by means of small 
filaments, or threads, which encircle the cesopha- 
gus like a necklace. The covering of their body 
is divided into a certain number of ring-like seg- 
ments, by transverse folds, having their integu- | 
ments sometimes hard, sometimes soft, but always 
with the muscles attached to the interior of the 
envelop. Their bodies have frequently articu- 
lated limbs attached to the sides, but they are 
also very frequently without any. We shall as- 
sign the term articulated animals (Anzmalia ar- 
ticulata) to denote this numerous division, in 
which we first observe the transition from the 
circulating system in cylindrical vessels of the 
higher animals, to a mere nutrition, by imbibing 
or sucking in the alimentary substances; and the 
corresponding transition, from respiration through 
particular organs, to one performed by means of 
tracheze, or air-cells, dispersed throughout the 
body. The senses most strongly marked among 
them are those of taste and sight. One single 
family exhibits the organ of hearing. The jaws 
of the articulated animals are always lateral, but 
sometimes they are altogether wanting.” As in- 
stances of this form, we may mention the earth- 
worm, leech, crabs, lobsters, spiders, beetles, grass- 
hoppers, and flies. From the circumstance of 
their coverings, or limbs, being divided, or joint- 
ed, they derive the name of “articulated,” from 
the Latin articulus, a little joint. 
4, Raprata—Radiated Animals. 
_ “To the fourth and last form, which includes 
all the animals commonly called zoophytes, may 
be assigned the name of radiated animals (Anz- 
ANIMAL CHEMISTRY. 181 
malia radiata). In all the other classes the or- 
gans of motion and of sensation are arranged 
symmetrically on both sides of a medial line or 
axis; while the front and back are quite dissim- 
ilar. In this class, on the contrary, the organs 
of motion and of sensation are arranged like rays 
around a centre; and this is the case even when 
there are but two series, for then both faces are 
similar. They approach nearly to the uniform 
structure of plants; and we do not always per- 
ceive very distinct traces of a nervous system, 
nor of distinct organs for sensation. In some we 
can scarcely find any signs of acirculation. Their 
organs for respiration are almost always arranged 
on the external surface of their bodies. The 
greater number possess, for intestines, a simple 
bag or sac, with but one entrance; and the low- 
est families exhibit nothing but a kind of uniform 
pulp, endowed only with motion and sensation.” 
The following are instances of this singular class 
of animals :—The sea-nettle, polypus, hydra, coral, 
and sponge. The name zoophyte is derived from 
two Greek words, ¢w» (zoon), an animal; duzo» 
(phyton), 2 plant; while that of radiata, derived 
from the Latin, evidently points out the radiated 
or TRtee arrangement of their parts. “ Before 
my time,” says the Baron Cuvier in a note to his 
first aft, “modern naturalists divided all In- 
vertebrated Animals into two classes— Insects 
and Worms. I was the first who attacked this 
view of the subject, and proposed another divi- 
sion, in a paper read before the Society of Natu- 
ral iations at Paris, the 21st Foreal, year ili. (or 
10th May, 1795), and which was afterwards printed 
in the ‘ Decade Philosophique.’ In this paper, I 
pointed out the characters and limits of the Mol- 
lusca, the Crustacea, the Insects, the Worms, the 
Kchinodermata, and the Zoophyies. The red- 
blooded worms, or Annelides, were not distin- 
guished until a later period, in a paper read before 
the Institute, on the 11th Nivose, year x. (or 31st 
December, 1801.) LI afterwards distributed these 
several dlncses into three grand divisions, analo- 
gous to that of the Animalia Vertebrata, in a 
paper read before the Institute in July 1812, and 
afterwards published Ha the Annales du mus. 
d’ Histoire Nat. tome xix,’ 
ANIMAL CHEMISTRY. Organic bodies are 
distinguished from inorganic by always consist- 
ing of two or more of a few elements, carbon, 
hydrogen, oxygen, and nitrogen, with a a 
others; by consisting usually of a large number 
of equivalents, and by consequently being com- 
plex in their composition ; by their ready decom- 
position or separation into simpler forms of mat- 
ter. Many of them have also a compound radi- 
cal, as basis, composed of two or three elements, 
carbon and hydrogen, or these with nitrogen, 
which act as elements combining oxygen, sulphur, 
&c., and their oxides with acids. We may dis- 
sauaanta between organic and organized bodies; 
the latter, while in connection with the plant or 
animal, partaking of its vitality and aac ass 
| 
