ZOOLOGICAL GARDENS. 
47 
cutting the herbage with the front teeth (incisors) of the 
lower jaw, against the toothless pad of the front of 
the upper jaw, and hastily swallowing the mouthfuls. 
After grazing they lie down and quietly rest, but when the 
feeling of hunger comes on, masses of food are brought back 
in boluses to the mouth for mastication, where they are 
triturated into an exceedingly fine pulp, mixed with a 
plentiful secretion of saliva, then again swallowed, but 
not returned to the cavity from whence the food came. In 
the first act of swallowing, it went directly to the paunch and 
to the reticulum , but in the second act it passed directly to 
the psalterium or many-plies , and from it finally to the 
abomasum or rennet stomach, in which it is subjected to 
the action of the gastric juice. The food is made to re¬ 
turn to the mouth by the action of the diaphragm, that is 
the transverse muscle that separates the chest cavity from 
the belly cavity, and by the contractions of the paunch 
and reticulum , the food is pressed up against the 
opening of the oesophagus or throat-tube between 
the paunch and reticulum . The oesophagus opens to re¬ 
ceive a portion of the food, and having received it, closes its 
orifice, and then by contracting from behind, pushes 
the bolus to the mouth, and this latter action can easily 
be observed in any animal ruminating. The food in re¬ 
turning is directed straight to the psalterium by a groove 
that proceeds from the oesophagus to the reticulum , and 
is shut off by a valve from the two first sacs of the stomach 
I 
whilst when the valve is open, the food passes directly 
into these two sacs. The action of the animal’s jaw 
while engaged in masticating the boluses, is peculiar, 
as after the first stroke, say from left to right, all the 
succeeding movements arc from right to left. 
