832 
ZOOLOGY. 
its taste. We may readily distinguish the pylorus, c, and 
beneath we perceive a part a little more protuberant, of an 
orange colour. Next we see the intestine, d d, somewhat re¬ 
sembling a colon ; it is much thicker than the stomach, es¬ 
pecially when it is full; it has also strong muscular fibres, 
which form it into folds, and therefore valves. When in 
action, this intestine becomes very thin, and contracts con¬ 
siderably. In examining the commencement of this con¬ 
traction, we discover a great number of little white threads, 
e e e\ these threads, which resemble small intestines, are at¬ 
tached to the colon throughout its whole length, but parti¬ 
cularly at the party, where the contraction begins; this 
connexion is very strong, and is made, by means of the tra¬ 
chea;, which are distributed through the whole body, but 
chiefly here. This intestine, after the contraction, of which we 
have spoken, dilates itself again at g, when it becomes en¬ 
tirely membranous; as it is transparent, it allows us to see 
some oblong white particles, h, traversing its whole substance. 
If we open the intestine, we find that they are glandulous 
bodies, six in number, which are raised in a remarkable 
manner on the internal surface of the intestine. The colon 
contracts itself once more at the part i, where it finishes, then 
the intestinum rectum, /, is met with, which terminates at the 
anus, immediately beneath the sting. 
In fishes, the alimentary canal is generally short; some¬ 
times, as in the petromyzon marinus, it runs straight from 
the oesophagus to the anus. The oesophagus is of great 
width, generally on account of the necessity that exists for 
this order of animals swallowing large substances, as they do 
not masticate. The enlargement of the stomach is very 
often so little, that this cannot be distinguished from the 
gullet. In the tetrodon hispidus the stomach is so large, and 
of so elastic a structure, that the fish can change itself from 
a long to a round shape, by distending it with air. Ordina¬ 
rily, the coats of the stomach are thin; but there are not 
wanting fishes that have it very thick and muscular. The 
intestines are of various lengths, generally short; but they 
are sometimes enlarged by a spiral valve, and nearly always 
by the appendices pyloricae, which Blumcnbach thus de¬ 
scribes :— 
“ The appendices pyloricse (which are found in all fishes, 
with a very few exceptions, as the pike) sometimes open at 
the lower orifice of the stomach, but generally at the com¬ 
mencement of the intestinal canal, and secrete a fluid, which 
seems to have considerable influence on the business of di¬ 
gestion and chylification, which is performed in these ani¬ 
mals in a very short time. They have generally the appear¬ 
ance of small blind appendices, and their number varies in 
the different species, from one to several hundred. In some 
cartilaginous fishes they are, as it were, consolidated into a 
glandular body, which has been compared to the pancreas 
of warm-blooded animals.” 
These appendices have been supposed to perform the same 
office as the liver in the superior orders; but this opinion is 
erroneous, since they co-exist with that organ : but the glan¬ 
dular structure of their parietes, renders it certain that they 
are the repositaries of some secretion. 
The letters c, d, e,f g, h, in fig. 26, mark the course of 
the alimentary canal in the squalus maximus. 
The alimentary canal of the conger eel is seen at fig. 28. 
In the amphibia we do not find any very remarkable 
change in the alimentary canal. Snakes have an oesophagus 
larger and still more elastic than fishes, and a stomach of the 
same dimensions—generally a short intestine. In the co¬ 
luber natrix this is not equal to the length of the animal; 
but its dimensions are enlarged by a fallopian valve, formed 
by the projection of the lesser intestine into the greater. 
The capacious size of the oesophagus enables these serpents 
to swallow, as we have elsewhere mentioned, animals of 
larger bulk than their own bodies; and it is curious to ob¬ 
serve how the part of their prey that is within the stomach is 
digested, while the rest remains sticking in the oesophagus 
unchanged. 
The turtle’s oesophagus is capacious, and is beset with 
numerous white pointed processes, which, Blumenbach con¬ 
jectures, serve to prevent the return of the food. The testudo 
caretta has an internal canal, five times as large as his body ; 
and in this, as in other species* the surface of the mucous 
membrane of the intestines is much extended by a multitude 
of thin longitudinal processes, which become fewer as the 
intestine descends. 
In the crocodile the most remarkable points in the ali¬ 
mentary canal, are the funnel-like shape of the oesophagus, 
and the thickness and muscularity of the stomach. 
At fig. 19, we have a view of the alimentary canal in frogs, 
in situ; p, the stomach and intestine; q , the liver; r, the 
gall-bladder. 
Of the alimentary canal in birds .—'The chief peculiarity 
of the alimentary canal in this order, are—1st. The crop, a 
dilatation of the oesophagus just before the sternum, furnished 
with numerous glands. 2d. A dilatation surrounded by 
glands, which is called the bulbus glandulosus, or, by Cuvier, 
the ventricule succenturie, 3d. The amazing thickness and 
muscularity of the stomach, constituting this viscus a gizzard. 
4th. The existence of two coeca. These peculiarities are ge¬ 
neral, but not universal; for the crop exists in land-birds 
only—the piscivorous fishes having an oesophagus so large 
and elastic, that the cavity can be dispensed with; the sto¬ 
mach is, in those birds who live on insects, only a thin 
membranous bag ; and some few aquatic birds have but one 
ccecum, and several predatory birds none. 
The termination of the rectum in a cloaca, or common 
receptacle for the ureters, the generative organs, and the 
aperture of a membranous mucus-secreting bag, called bursa 
Fabricii, are peculiarities always met with. 
At the entrance of the alimentary canal in birds, a num¬ 
ber of small mucous glands are generally found that facilitate 
deglutition, and defend the membrane. In the ostrich two 
of these are so large that they appear like tonsils. These, 
however, bear no analogy to those salivary glands of the 
higher animals; for as there is no trituration performed in 
the mouth of birds, parts for the secretion of a solvent fluid 
would be clearly misplaced. 
A throat-sac is also met with in some birds; this is a dila¬ 
tation of the lining of the mouth between the lower jaw. It 
is most remarkable in the pelican, which has it large enough 
to contain several quarts of water and the fishes that form its 
prey. The buzzard has one of a somewhat different kind in 
the front of the throat, which opens by a large orifice at the 
root of the tongue. 
It is to be remarked, that considerable varieties in size and 
form, are met with in the parts previously described. These 
we cannot better illustrate, than by extracting from the notes, 
appended by Messrs. Lawrence and Coulson to Blumenbach’s 
“ Manuel of Comp. Anat.,” the following observations:— 
“ The solvent glands in birds are larger, and more distinct 
from the other parts of the digestive organs than in the mam¬ 
malia. The solvent glands in the whole of the extensive 
genus falco, of Linnseus, are cylindrical bodies, with very 
small canals, a villous internal surface, and thick coats, open 
at one end, closed and rounded off at the other; they are 
placed on the outside of the membrane which lines the car¬ 
diac cavity, they lie parallel to one another, and nearly at 
right angles to the membrane through which they open, the 
closed end being slightly turned upwards, so as to make the 
orifice the most depending part. In the golden eagle (the 
falco chrysaetos, L.) and the sea eagle (falco ossifragus,) 
they form altogether a broad compact belt; but in the hawk 
(falco nisus) this belt is slightly divided into four distinct 
portions; immediately below these glands the cavity be¬ 
comes wider, and is enclosed in a digastric muscle of weak 
power, with a flat tendon on each side. The internal sur¬ 
face of this cavity, which is the gizzard, is soft and vascular. 
“In all animals that live on animal food, the solvent 
glands appear to have a similar structure to that which has 
been just described, only differing in size and situation. 
In the solan goose (pelecanus bassanus) these glands are 
rather larger than in the eagle, but are placed in the dilated 
part of the cavity of the gizzard, forming a complete belt of 
great breadth, consequently are extremely numerous. 
“ In 
