284 



THE SENSORIAL FUNCTIONS. 



brane."* A transverse and vertical section of these parts is 

 given in Fig. 3S3.t The turbinated bones are curionsly 

 folded, and often convoluted in a spiral form, with the evi- 

 dent design of obtaining as great an extent of surface as pos- 

 sible within the confined space of the nasal cavity. This tur- 



binated, or spiral shape, chiefly cliaracterizes these bones 

 among herbivorous quadrupeds: in the horse, for example, 

 the turbinated bones are of a large diameter, and extend the 

 whole length of the prolonged nostrils. Their structure is 

 exceedingly intricate; for while they retain, externally, the 

 general shape of an oblong spiral shell, they arc pierced on 

 all their internal sides with numerous perforations, through 



• This fig-ure sliows the branches of the olfactory nerve (o,) passing 

 through tlie thin cribriform plate of the ethmoid bone, and distributed over 

 that membrane. Several of the cells, which open into the cavity, are also 

 vSecn; such as the large sphenoidal sinus (s,) the frontal sinus (f,) and one of 

 the ethmoidal cells (c.) s, is the nasal bone; p, the palate; and e, the 

 mouth of the Eustachian tube, which leads to the ear. 



■|- In this figure, s, is the septum, or partition of the nostrils, on each side 

 of which are seen the sections of the turbinated bones projecting into the 

 cavity; the ethmoid cells (c,) situated between the orbits (o;) and the An- 

 trum maxillare (a,) which is another large cavity communicating with the 



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iiostrils. 



