////: lirsi'lllATnliY .l/'/M//.r/TS /.V .W.I. W.W.I /./.I. 



1'r'iHinition. liVnn'W' ill' I.>\\,T j:i\v fnun thri-.- ln-a<l*. On tin- lii>t ut these make 

 t\\o tnm>\ rrs> sri'tions, inn- passing hrt\\n'ii tin- .-ci'iniil iinil thin! molar l<x>t!i. tin ntlii-r 

 Ix-hintl tlif tlctitiil iiirmlt.'. Saw tlirouu'li iln- S'-i-nml In ail longitudinally nnd v. rti-;illy. a 

 littlf to one side of the median line. On tin- thiril makr a Imri/nntal n-rtion in uurh u 

 manner as to obtain an inferior portion analogous to tlmt shown in luur.- -j.'.. 



1. The Nostril*. 



The nostrils are two oblong, lateral openings, situated at the extremity 

 of the nose, circumscribed by lips or movable wings (alee) disposed in an 

 oblique direction do wnwards and inwards, and slightly curved on them- 

 selves, so as to present their concavity to the external side. 



The lips or alte of the nostril are enveloped, inwardly and outwardly, by a 

 thin, delicate skin, covered by fine, short hairs. The external is concave on 

 its free margin ; the ////'/;//// is convex. The commissure which unites these 

 two wings superiorly, forms a slight cross curved inwards. When the finger 

 is introduced into this commissure it docs not enter the nasal cavity, but the 

 false nostril : a conical pouch formed by the skin, extending to the angle 

 comprised between the nasal spine and the elevated process of the pre- 

 maxillary bone. 



In the Ass. according to Goubaux, the false nostril is areolated at the 

 posterior extremity, which ascends beyond the summit of the re-entering 

 angle formed by the nasal and premaxillary prolongation. 



The inferior OONMMMMT0 is round and wide, and, towards the bottom, 



presents an opening, sometimes double, which looks as if punched out ; this 



is the inferior orifice of the lachrymal duct, which, in the Ass and Mule, is 



carried to the inner face of the external wing, near the superior commissure. 



STRUCTURE. The nostril is composed of a cartilaginous frameioorlc, 



'"-.sc/rx to move it, and mfepWMNb, vessels, and nerves. 



Cartilaginous framework (Pig. 222). This framework is formed by a 

 cartilage, bent like a comma, and which, in its middle 

 part, lies against that of the opposite side, the two 

 making a kind of figure X. Fixed in a movable 

 manner to the inferior extremity of the middle septum 

 of the nose, by means of short interposed fibres, this 

 cartilage offers : a wide upper part, situated in the 

 substance of the inner wing of the nostril, and covered 

 by the transverse muscle of the nose (Fig. 222, 1) ; 

 and an inferior portion, which, after passing into the 

 lower commissure, is prolonged, in a bluut point, to 

 the external wing, where it receives the insertion of 

 several fasciculi belonging to the orbicularis muscle 

 of the lips, the pyramidal muscle of the nose, and 

 the supernaso-labialis (Fig. 222, 2). Each wing, 

 therefore, possesses a cartilaginous skeleton ; but that 



CAETILAOIOrTHE<K. f &* ** ^ J^ "^P^ j. 11 "**- 



i, 1, Wide portion, form- ^ence of its being only formed by the inferior ex- 



ing the base of the inter- tremity of the common cartilage, 

 na! wing of the nostril ; This cartilage, it will bo understood, sustains the 



2, 2, Narrow extremity Q^ o f the nose, prevents their falling inwards, and 



1'i-olonged into the ex- a j wa y g keeps open the external orifices of the re- 



terual wine; 3, Superior . \ 

 or anterior 8 border 5 the spiratory apparatus 



aeptum. Muscles. Ihe motor muscles of the alee are all 



dilators in the domesticated animals. They are : the 



fransvertalis nav (ililnfntnr naris anterior Percivall), or transversalis of the 



Fig. 222. 



