VII.] 



UNGULATA. 



97 



In the Pig (Fig. 36) and Hippopotamus the presternum is 

 compressed and keeled ; the articular facets for the first 

 pair of ribs are close together on its upper surface ; but the 

 mesosternum is broad and flat, the first segment being 

 transitional, compressed in front, and broad posteriorly. 



FIG. 35. Sternum and sternal ribs of 

 the Red Deer (Cennts elaphus), \. fs 

 presternum ; ms mesosternum ; xs 

 xiphisternum. 



FIG. 36. Sternum of the Pig (Ss 

 scrofa), \. ps presternum; ms 

 sternum ; .vs xiphisternum. 



The xiphisternum is narrow and pointed. The sternum of 

 the Pig very often retains indications of the primordial 

 median fissure through life. 



The Horse and the Tapir have a very peculiar sternum. 



H 



