RUMINANTIA. A423 
or reed) and is here acted upon by the gastric juice. Professor Garrod 
thus describes the probable order of events in the act of rumination: 
“« The paunch contracts, and in so doing forces some of the food into 
the honeycomb bag, where it is formed into a bolus by the movement 
of its walls, and then forced into the gullet, from which by a reverse 
action it reaches the mouth, where it is chewed and mixed with the 
saliva until it becomes quite pulpy, whereupon it is again swallowed. 
But now, because it is soft and semi-fluid, it does not devaricate the walls 
of the groove communicating with the manyplies, and so, continuing on 
along its tubular interior, it finds its way direct into the third stomach, 
most of it filtering between the membrous laminz on its way to the 
fourth stomach, where it becomes acted on by the gastric juice. After 
the remasticated food has reached the manyplies, the groove in the 
reticulum is pushed open by a fresh bolus, and so the process is repeated 
until the food consumed has all passed on towards the abomasum or 
true digestive stomach.” 
The ruminants are peculiar also in their dentition ; in the so-called 
true ruminants there are no incisors or cutting teeth in the upper jaw, 
but the teeth of the lower jaw are opposed to a hard callous pad ; the 
herbage is cropped by being nipped between these teeth and the pad, 
and detached by an upward motion ; in some few, such as the musk 
deer, Chinese water deer and the rib-faced deer or muntjac the upper 
canines exist, and are largely developed. 
The camels and llamas possess two cutting teeth in the upper jaw, 
and in this respect they differ from the true ruminants, as also in some 
internal features. 
The grinding teeth are six on each side of the jaw, and are composed 
of alternate convolutions of enamel, dentine and cement, which wear 
unequally by the lateral motion of grinding, and so form the necessary 
inequality of surface. 
The centre metacarpal bones in the Ruminantia are fused into one 
common bone, except in the deerlets, which also have the two outer 
fore and little finger metacarpals distinct, whereas they are but rudi- 
mentary in the rest of the true ruminants, and totally absent in the 
camels, 
The following is the classification at present adopted: SuB-ORDER 
Ruminantia, containing two sections, viz. True Ruminants and the 
Camels (Zylopoda). Section Zrue Ruminants, containing two divisions, 
viz. Horned Ruminants and Hornless Ruminants, such as the chevro- 
tains or deerlets (Zragulide). Division Horned Ruminants, containing 
two groups, viz. Hollow-horned Ruminants (Sovid@), and Solid-horned 
Ruminants (Cervide). The deerlets possess no psalterium or third 
stomach, except in a rudimentary form, and their feet approximate to 
those of the pigs, and they are destitute of horns. The hollow-horned 
