466 
OWEN ON RUMINANT QUADRUPEDS. 
have been exposed a long time in the open prairie or 
savannah, before it had filled its stomach. Its chances of 
escaping a carnivorous enemy would have been in a like 
degree diminished. But by the peculiar structure of the 
ruminating stomach, the grass can be swallowed as quickly 
as it is cropped, and be stowed away in a large accessory 
receptacle, called the “rumen,” or first cavity of the stomach; 
and this bag being filled, the ruminant can retreat to the 
covert, and lie down in a safe hiding-place to re-masticate its 
food at leisure. 
The modifications of the dentition, oesophagus, and stomach, 
by which the digestion in the Ruminantia is carried out, 
were described and illustrated by diagrams. 
The speaker next treated of the various kinds of horns 
and antlers : the manner of growth, shedding, renewal, and 
annual modifications of the deciduous horns, the peculiarities 
of the persistent horns, the mechanism of the cloven foot, 
and the provision for maintaining the hoofs in a healthy 
condition, were pointed out. 
The following were the chief varieties of the ruminating 
stomach. In the small musk-deer ( Tragulus ) there are three 
cavities, with a small intercommunication-canal between the 
second and last cavity ; the “ psalterium,” or third cavity, in 
the normal ruminating stomach, being absent. This cavity 
is likewise absent in the camel-tribe, which have the cells of 
the second cavity greatly enlarged, and have also accessory 
groups of similar cells developed from the rumen, or 
first cavity. These cells can contain several gallons of 
water. The relation of this modification, and of the hump 
or humps on the back, to the peculiar geographical position 
of the camel-tribe was pointed out. 
The modifications of the ruminating stomach ; the dis- 
covery of rudimental teeth in the embryo Ruminantia , which 
teeth (upper incisors and canines) have been supposed to 
characterise the Pachyderms ; the occurrence of another 
alleged pachydermal character, viz., the divided metacarpus 
and metatarsus, in the foetus or young of all ruminants, and 
its persistence in the existing Moschus aquaticus , and in a 
fossil species of antelope ; the absence of cotyledons in the 
chorion of the camel-tribe, with the retention of some incisors 
as well as canines in the upper jaw of that tribe ; the ascer- 
tained amount of visceral and osteological conformity of the 
supposed circumscribed order Ruminantia with the other 
artiodactyle (even-toed) Ungulata; above all, the number of 
lost links in that interesting chain which have now been 
restored from the ruins of former habitable surfaces of the 
