Practical Course. 97 
1 
Clear the digestive tract throughout its entire length, by cutting 
through the mesentery, noticing the small red spleen, which is attached 
to the mesentery near the back of the abdominal cavity. 
Observe that the digestive tract is a winding tube which extends 
from the mouth in front to the cloacal aperture behind. Make out the 
following parts in it:— 
(1) The mouth in front, 
(2) The soft thin-walled gullet (cesophagus), which connects the 
mouth with the stomach. 
(3) The elongated stomach, with thick glandular walls. 
(4) The narrow coiled tube (small intestine) which lies behind 
the stomach, The anterior end being the duodenum, into 
which the bile and pancreatic ducts open. ° 
(5) The large intestine, which connects the small intestine with 
the cloaca. 
Endeavour to make out the pale-coloured gland (pancreas) which 
lies near the commencement of the small intestine. 
On either side of the stomach above, observe the large pulmonary 
air-sacs or lungs, -Endeavour to make out the short air-passage 
(laryngo-tracheal chamber) by which the lungs are connected with the 
slit-like glottis in the floor of the mouth. 
Fixamine the dark-red elongated kidneys and endeavour to make out 
the ducts by which their secretion passes to the cloaca. 
In the male male out the pair of yellowish rounded testes, which lie 
in front of the kidneys. Their ducts enter the kidneys and com- 
municate with the ducts of these organs, 
In the female notice the broad convoluted ovaries, in which you will 
usually be able to see numerous little dark-coloured eggs. The eggs 
pass out by a pair of much convoluted ducts (oviducts) which enter 
the cloaca. 
Cut away the digestive, reproductive, excretory and pulmonary 
organs, so as to clear the body cavity and expose the spinal nerves, 
Also cut away the lower jaw. Observe the slender white spinal nerves 
whick issue from the spinal column on either side. In the posterior 
part of the abdominal cavity these nerves are large and numerous, where 
they constitute what is kwown as the sciatic plexus. Follow down these 
nerves on one side where they enter the leg, cutting away the muscles 
and bone, and see how they unite to form the large sciatic nerve of the 
leo. Notice the large brachial nerve which supplies the fore-limb and 
follow it back to where it issues from the spinal column, . 
Look for the delicate nerve cords, with swellings (ganglia) at inter. 
vals, which connect the roots of the spinal nerves with each other 
H 
