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MAMMALIA. 
After the paunch comes the bonnet or cap of the stomach (c) ; 
this receptacle is small, and its internal mncons membrane is 
lined with folds formed by polygonal cellules. In this cap the 
food is gradually moulded into small pellets, which ascend again 
into the mouth, by means of a natural movement, and not a con- 
vulsive or irregular one, as in other animals ; these pellets then 
undergo a thorough mastication and salivation. Such is “ chewing 
the cud.” 
When the food, thus transformed into a soft and nearly fluid 
paste, descends again into the stomach, it goes straight into a third 
intestine, called the omasum or leaf (d), on account of the wide 
longitudinal folds which line the interior of it, much resembling 
the leaves of a book. From this it at length passes into the 
digesting stomach, or rennet-bag ( e ), which is the seat of the real 
digestion, and owes its name to the fact that its irregularly folded 
internal surface is continually moistened by the gastric juice, a 
fluid which has, as is well known, the property of curdling milk. 
After having undergone the digestive process, the food passes 
from the rennet-bag (e) into the intestine duodenum (/). We 
must add that liquids pass straight into the digesting stomach 
without staying either in the paunch or bonnet. 
Ruminants feed chiefly upon grass, both stalks and leaves, and 
their dental system is specially adapted to such circumstances. 
There are no incisors in the upper jaw, and there is an empty 
space between the lower incisors and the grinders, the crowns 
of which are wide and marked with two double crescents. At 
the time of mastication, the movement of the jaws is nearly 
circular. 
The feet of all these animals terminate in two toes, the meta- 
tarsal and metacarpal bones of which are joined together in one 
bone, called the shank. Sometimes, also, there exists at the 
back of the foot two small spurs, vestiges of lateral toes. In all 
these animals, except Camels and Llamas, the hoofs, which 
entirely cover the last joint of the two toes on each foot, act 
side by side on a smooth surface, and resemble one single but 
cloven hoof. Thus the origin of the word cloven-footed. 
We must remark, in conclusion, that these animals are the only 
Mammals which are provided with bony extensions of the frontal 
bones ; but all the Ruminants do not possess these. 
