224 



THE ANATOMY OF THE HOBSB. 



but for the greater part of its extent the partition is composed of a plate 

 of cartilage— the septal cartilage. This septal cartilage is continuous 

 above with the perpendicular plate, which is merely an ossified portion 

 of it ; behind it is received into the cleft of the vomer, and expands on 

 the premaxillary suture ; in front it expands on the inner aspect of the 

 internasal suture ; and inferiorly the alar cartilages are movably con- 

 nected to it. 



The Inferior Extremities of the nasal fossee are termed the inferior 



Fig. 28. 



Transverse Section through the Nasal ChambJ'^rs. 



1, Anterior tvirbinated bone ; 2. Posterior turbinated bone ; 3. Anterior meatus ; 4. Middle 

 meatus ; 5. Posterior meatus ; C. Septum nasi. 



nares, or, in common language, the nostrils. They have already been 

 described (page 180). 



The Superior Extremities are separated from the cranial cavity by the 

 cribriform plate of the ethmoid bone, and are occupied by the lateral 

 masses of the same bone. Below and behind these are the superior 

 nares — the large patent orifices by which the nasal fosste communicate 

 with the pharynx, the right and left openings being separated by the 

 vomer bone. 



The following openings into the nasal fossa should be found : — 

 1. The Opening of the Lachrymal Duct (ductus ad nas>im). — Look for 

 this on the floor of the nasal fossa, a few inches within the nostril. It 

 is easily seen in the living animal, and has already been referred to in 



