zoo 
fly, moth. —Rhipiptera, xenos, stylops. — Diptera, gnat, 
house-fly. 
Class IV. Zoophyta. —Echinodermata, star-fish, echinus. 
—Entozoa, fluke, taenia, hydatid.—Acalephaa, actinia, me¬ 
dusa.—Polypi, hydra, coralline, pennatula, sponge.—Infu¬ 
soria, brachionus, vibrio, proteus, monas. 
In the remainder of this article, we have to furnish an 
account of the anatomy of the animals previously spoken of. 
Two roads lay open to us: one to commence with an analysis 
of each genus or species, a mode very complete and desirable; 
the other to give merely such an account of the leading sys¬ 
tems, in the different orders, as may best illustrate the general 
differences. This incomplete sort of exposition, is what is 
usually adopted by writers on General Zoology, and this our 
limits compel us to adopt. We shall now proceed to give an 
account of 
The systems of Repair and Waste in general: 
viz. the Digestive, Circulating, Respiratory, Urinary, Cu¬ 
taneous, and Generative. 
In the class vermes, the stomach presents many varieties. 
In general, it is a mere membranous bag; but in the aphro¬ 
dite aculeata, in the helix stagnalis, and the orchidia, its 
muscular structure is developed so as to make it a sort of 
gizzard. Again, the oesophagus in many of the testacea is 
furnished with hard processes, which serve to triturate the 
food. In the cuttle fish, for example, there are two teeth, or 
rather jaws, in the oesophagus; the bulla lignaria has three, so 
powerful as to crush very strong shells; the stomach of the 
chiton cinereus is studded with small grinders ; the trictonia 
has two jaws, which act like scissars; the leech has three se¬ 
micircular cutting plates, just within the mouth. 
The size, the form, and the connexions of all these parts, 
vary considerably; and the teeth above mentioned, are peri¬ 
odically shed, like the cutaneous scales or feathers of the 
higher animals. 
The intestines vary in the vermes, as much as the stomach. 
In the ascaris lumbricoides it is merely a canal, nearly 
straight, that runs from the stomach to the anus; in the hirudo, 
the intestines contract towards their termination, and end in 
an anus so minute, that some, (Dumeril amongst others) have 
denied its existence altogether; in the aphrodite aculeata, as 
well as in several other vermes, the intestine has several 
blind pouches of considerable dimensions, entering it on 
different sides; these, Zoologists have described, as furnishing 
peculiar secretions, or forming receptacles for the aliment; 
they perform, probably, both these functions. It is curious 
that in all the acephalous mollusca, the intestine passes 
through the heart. 
In the annexed engravings are specimens of these parts. 
Fig. 1.— a a, the two larger horns of the helix pomatia; 
l b, the smaller horns; c,themouth; d, the opening (visible 
only during the rutting season) out of which the generative 
organs unfold themselves; e, the limbus, a thick border, 
which adheres to the edge of the shell, having two orifices; 
one, g, for the passage of air, the other,,/) for the reception of 
air ; h, the foot of the animal, which, being protruded from 
the shell before and behind, serves for locomotion; 11, the 
body of the animal; n, the situation occupied by the heart. 
At fig. 2 is seen the alimentary canal of this helix; c, 
the stomach ; d , the pylorus ; b, the small intestines which, 
having made several turns corresponding with the body, end 
in the rectum, at d; the anus, e, is, as before shewn, on the 
side of the border that unites the animal to the edge of this 
shell. The liver is situated in the midst of the small intes¬ 
tines; at e, is the part where the bile is poured into the intes¬ 
tines. At fig. 3 are seen the same parts from the other 
side, a marking the liver, b the intestines, c the rectum, and 
d the stomach. 
In the insecta we have the same kinds and varieties in 
the stomach and intestines as in the preceding order.— 
In the earwig we have rows of teeth round the upper orifice 
of the stomach, and in many species of cancer bony processes 
in the stomach, which are annually re-produced. Among 
other curious deviations, it may be mentioned that the grass- 
L O G Y. 831 
hopper has the oesophagus larger than the stomach; and 
that one species (the gryllus gryllotalpa) has the stomach 
divided into three or four cavities, which have been com-! 
pared with the stomachs of the ruminating animals. 
In some, as in the Crustacea, the canal takes a.direct course 
from the mouth to the anus, and is only enlarged at the sto¬ 
mach. The orthoptera, on the other hand, have a long, and 
complicated digestive apparatus; first, a membranous sto¬ 
mach, then one that is muscular and toothed, thirdly some 
coecal processes, and fourthly an intestine of various length 
and calibre. As an universal rule, it is found that animals of 
the same order, living on animals, have a shorter alimentary 
canal than those which live on vegetable matter; but there 
is a great connexion between the size of the canal and the 
voracity of the animal. Thus the larvae of the scarabseus and 
the butterfly have intestines ten times as large as they have 
when they become winged insects. 
The simplest form of the alimentary canal in the insecta is 
seen at fig. 6, which is the stomach and intestines in the 
ephemera. 
The oesophagus passes like a thread to the entrance of the 
stomach a ; c, the stomach, with the trachaea ramifying upon 
it; A, its superior opening; o', the small intestine; e, the large; 
f the rectum. The stomach is placed close to the back, aud 
within the fourth and fifth rings of the body. 
As another example of the anatomy of the alimentary ca¬ 
nal in the insecta, we have taken the louse. Fig. 5 is a re¬ 
presentation of the stomach and intestines of this insect, in 
which the mouth, a, is an opening, so small that it can rarely 
be detected; but its existence may readily be demonstrated 
by examining the insect while he is sucking blood ; for, from 
the transparency of its parietes, this fluid is seen passing into 
the mouth with a velocity, which, Swammerdam says, “ is 
enough to frighten the observer.” The mouth is seated at 
the extremity of a proboscis, and is moveable therein ; its ex¬ 
treme sharpness enables it to penetrate the human skin very 
readily. The proboscis is armed with sharp claws, which 
bury themselves readily in the skin, and serve to hold the 
mouth immoveable when insinuated into the insect’s prey. 
The oesophagus lines the whole length of the proboscis, and 
terminates in the stomach. It is situated at x, behind the 
eyes, passes over the brain, forms a small swelling in the neck, 
g, contracts itself considerably immediately afterwards, h, and 
finally enters into the stomach by an opening, of a diameter 
so small, that it is never visible except while the animal is 
sucking. At i i, we observe the stomach partly contained in 
the thorax and loins, but chiefly in the abdomen, while in 
the chest it has entering into it two blind pouches, k k, which 
are extended on each side of the oesophagus and medulla 
spinalis, even to the first pair of feet. In the abdomen the 
stomach is in form an elongated sac, and is remarkable for 
the amazingly extended and powerful contractions it exhi¬ 
bits, as well as for the thick manner in which it is studded with 
trachese, til-, and these tracheae have been considered by some 
as furnishing, by their alternately swelling and contracting, the 
intestinal movement of the alimentary canal. A small body, 
in, of irregular size and, in different insects, extremely variable 
figure, is found in the abdomen, just beneath the stomach; 
it furnishes a secretion to the alimentary canal, and thus an¬ 
swers to the liver or pancreas of the higher animals, or per¬ 
haps to both. At the extremity of the stomach we have the 
pylorus, n, followed by the small intestine, o o, which is much 
convoluted, and, like the stomach, thickly covered with the ra¬ 
cemes of the trachem. Four large vessels enter it at pp pp, 
to which Malpighi gave the indeterminate name of varicose 
vessels but which Swammerdam shewed to be coeca. Soon 
after these the colon becomes visible at (j. A large dilatation 
at r may be considered as the cloaca, terminating in the 
rectum, s, at the extremity of which is the anus, t, that opens 
under the belly of the insect at the bifurcation of the tail. 
The preceding may, in some measure, be contrasted with a 
representation ot the same parts in the bee, at fig. 10. 
The oesophagus, a, fig. 10,is very thin, and the stomach, b, is 
membranous and thin ; it is fortified by fleshy fibres, and is 
generally found full of honey, which is easily recognised by 
its 
