80 
COMPARATIVE ZOOLOGY. 
the intestines end in a large bladder-like expansion. Scor¬ 
pions have no stomachal cavity—a straight intestine passes 
directly through the body. 
In bivalve Mollnsks, like the Clam, the month opens 
into a short oesophagus which leads into the stomach, 
which lies imbedded in a large liver, and the intestine, 
describing a few turns, passes directly through the heart. 40 
In the univalve Mollnsks, like the Snail, the gullet is long,, 
and frequently expands into a crop; the stomach is often 
double, the anterior being a gizzard provided with teeth 
for mastication; the intestine passes through the liver, 
and ends in the fore-part of the body, usually on the right 
side. 
The highest Mollusks, as the Cuttle-fish and Nautilus, 
exhibit a marked advance. A mouth with powerful man¬ 
dibles leads to a long gullet, which ends in a strong mus¬ 
cular gizzard resembling that of a fowl. 41 Below this is a 
cavity, which is either a stomach or duodenum ; it receives 
Pig. 44.—Alimentary Canal of the Oyster: a , stomach 
laid open; d , liver; 6, c, d,f, convolutions of the intes¬ 
tine; g, anal aperture; n, o, auricle and ventricle; l, 
m, adductor muscle; h , k , lobes of month divided to 
show the venous canals at the base of the gills. 
the bile from a 
large liver. The 
intestine is a tube 
of uniform size, 
which, after one or 
two slight curves, 
bends up,and opens 
into the “funnel” 
near the month. 
Fishes have a 
simple, short, and 
wide alimentary 
canal. The stom¬ 
ach is separated 
from the intestine 
by a narrow “ py¬ 
loric” orifice, or 
