1074 ORGANS OF SPECIAL SENSE 



(nasal) branch of the ophthalmic nerve; the Vidian nerve; the posterior superior and posterior 

 inferior nasal and the anterior palatine from the spheno-palatine ganglion (p. 972); the anterior 

 superior alveolar from the infra-orbital division of the maxillary nerve (p. 968). 



The development of the nose, The nasal cavity makes its appearance as a depression of 

 the ectoderm on either side of the median line, immediately in front of the oval fossa, with which 

 the depressions are at first continuous. Later, by the union of the maxillary and globular proc- 

 esses (see p. 1076), the depressions are separated from the anterior part of the oral fossa, and this 

 separation is continued by the formation of the palatal processes of the maxilte and palatine 

 bones, so that finally the nasal cavities communicate posteriorly only with the pharynx. 



The cartilage which forms the lateral walls of the nasal fossa 1 is at first quite smooth, but 

 later it becomes eroded by absorption, whereby the nasal conchas are formed. The erosion also 

 extends into the neighbouring bones, the frontal, sphenoidal, and maxillary sinuses, and the 

 ethmoidal cells being formed in this manner, and being, accordingly, lined by mucous membrane 

 continuous with that of the nasal cavities. 



