86 COMPARATIVE ZOOLOGY. 
cavities—the thorax, containing the heart, lungs, ete.; and 
the abdomen, containing the stomach, intestines, etc. The 
e MBS e 
SSS 
R = 
<NeS; 
iS 
~ = 
Cp — seus 
Fic. 50.—Ideal Section of a Mammalian Vertebrate: A, pectoral, or fore limb; B, 
pelvic, or hind limb; a, mouth; 6, cerebrum; ¢, cerebellum; d, nose; e, eye; J, 
ear; g, esophagus; h, stomach; 7, intestine; j, diaphragm, or midriff ; ’, rectum, 
or termination of intestine; 7, anus; m, liver; m, spleen; 0, kidney; p, sympa- 
thetic system of nerves; g, pancreas; 7, urinary bladder; s, spinal cord; u, ure- 
ter; v, vertebral column; w, heart; 2, lung; y, trachea, or windpipe; z, epi- 
glottis. 
cesophagus passes through a slit in the diaphragm, and al- 
most immediately expands into the stomach. 
In the majority of Mammals, the stomach is a muscular 
bag of an irregular oval shape, lying obliquely across the 
abdomen. In the Flesh-eaters, whose food is easy of soln- 
tion, the stomach is usually simple, and lies nearly in the 
f course of the alimentary ca- 
nal; but in proportion as 
the food departs more wide- 
ly in its composition from 
the body itself, and is there- 
fore more difticult to digest, 
we find the stomach increas- 
ing in size and complexity, 
and turned aside from the 
general course of the canal, 
Fie. 51.—Section of Horse’s Stomach: A, Domes US retain the food e 
left sac; B, right sac; C, duodenum. longer time.” The inlet, or 
opening, into the cesophagus is called cardiac ; the outlet, 
