514 CHORDATA. 
The ox, on the other hand, starts from the bunodont 
type found in the pig, with four principal crowns. These 
do not unite transversely, but each independently becomes 
crescentic, producing the se/enodont or crescentic type of 
molar. The crescents may unite longitudinally but not 
transversely. 
The study of the teeth of these two types shows that 
in this respect the ox is more specialised than the horse, 
a conclusion which agrees with the comparative structure 
of the stomach. The stomach of the horse is fairly simple ; 
it is at most constricted into cardiac and pyloric portions, 
whereas that of the ox has four distinct parts or chambers. 
Fig. 353-—STOMACH OF A RUMINANT, SHOWING INTERNAL 
STRUCTURE. 
(FLoweErR and LypDEKER.) 
a, (Esophagus; 4, Rumen (paunch); c, Reticulum (honeycomb) ; d, Psalterium 
soul (many-plies) ; e, Abomasum (reed); 7 Duodenum. 
The rumen (or paunch) is a large and capacious sac for 
storage of food; the veticudum (or honeycomb bag) is a 
small globose sac with reticulate walls: following this 
is the psalterium (or many-plies) with folded walls, suc-. 
ceeded by the abomasum (or reed) which is the true 
digestive stomach. The food is cropped and swallowed, 
passing down to the paunch, in which it is stored. After 
feeding, the animal retires to a secure retreat or at least 
comes to rest, and the food is passed by the reticulum 
up the cesophagus into the mouth. Here the process of 
