70 



COMPAEATIVE DENTAL ANATOMY 



cusp which is called the metacone, in the upper 

 arch. In fact the upper cusps are distinguished 



Fig. 18. — Occlusal view of teeth of Opossum (Didelphis virginiana), 

 showing triangular molar crowns. 



by the ending 



the ending ' ' conid. ' ' 



and the lower cusps by 

 This gives three cusps 



