XIII 



PHYLUM CHORDATA 



571 



of this orjjan reaches its extreme limit in the ruminant Unfjulata 

 and in the Cetacea. In a typical Ruminant (Fig. 1198, E, Fig. 

 1199), such as a sheep or an Ox, the stomach is divided into four 

 chambers — the rumen or paunch, the reticulum, the ^^saZ^crt^'.m, 



Fici. ir.'s. — Different fonus iif tlic stomacll in Mammals. A. Dog; ;;, HSus decumanus ; 

 C. Mus musculus ; D, VTeasel ; E, schemeof the ruminant stidnach, tlie arrow with 

 the dotted line showing the eourse taken by the food : /•, human stomach ; 6', Camel J 

 H, Echidna aculeata ; /, Bradypus tridactylus. A. (in E and G) abomasum ; Ca. 



cardiac end ; Cuifi, greater curvatuie ; Vmt, lesser curvature ; Dv.. duodenum; JiiJ, cseetim ; 

 0, psalterium ; Ot. CKSophagus ; P. pj-lorus ; R. (to the right in Fig. E) rumen ; R (to the left 

 in Fig. E) reticulum ; Sc. cardiac division ; .S/<, pyloric division ; W. Z, water-cell.s. (From 

 Wiedeisheim's Comparative Anatomy.) 



and the ahomasum, or rennet-stomach. The first of these (Fig. 

 1199, li) is rauch larger than the rest; its mucous membrane 

 is beset with numerous short villi. The reticulum (c), which 

 is much smaller than the rumen, has its mucous membrane 



