298 



MAMMALIAN ANATOMY 



triangle is above. The inner outline is nearly vertical ; the outer 

 border is directed from above downward and outward ; the lower 

 border is pointed in the middle, encroaching on the lower surface as 

 an elevated process, from which the delicate scrolls which form the 

 surface seem to arise. As a whole, the surface is concave from above 

 downward and convex from side to side, and faces downward and 

 forward and toward the upper surface of the maxillo-turbinal. 



The posterior surface of the lateral ethmoid forms one-half of the 

 upper surface of the cribriform plate (Fig. 243). 



The lower surface of the lateral ethmoid (Fig. 217) is exposed 

 when the vomer is removed. It is triangular, wider in front than 



FIG. 217. 



Anterior End of Mesethmoid. 



Lower Anterior Portion of 

 Lateral Ethmoid. 



Anterior End of Vomer 

 with Maxillary. 



Vomer, with Palatine. 

 Vomer. 



Vomer, with Presphenoid. 



Lower Posterior Portion of Lateral Ethmoid 

 contained in Sphenoidal Sinus. 



THE ETHMOID AND VOMER, LOWER ASPECT. 



behind. The inner edge is longitudinal, and the outer edge is directed 

 backward and inward. The posterior half of the surface is formed of 

 the under surface of the largest lowest scroll, whereof the rounded 

 posterior end is received into the sinus in the presphenoid. In front 

 of the scroll and continued for a short distance along the outer border 

 is a small flattened area which represents the lower extended portion 

 of the seventh inner scroll. An incision visible in front and on the 

 outside is the lower end of the cleft on the external surface. On the 

 inside are the roots of several plates on the inner surface of the 



