X ENTERIC CANAL 49S 



or masticated and mixed with the saliva before passing 

 down the gullet, and thus digestion begins in the 

 mouth. 



The infra-orbital salivary gland is a large, lobulated, pinkish mass 

 situated in the antero- ventral region of' the orbit, below and in front of 

 the eyeball : its duct passes downwards to open into the mouth, nearly 

 opposite and externally to the second premolar. Th&J>arotid gland is 

 a soft, irregular, flattened organ, lying close beneath the skin, just 

 below and in front of the base of the external ear ; its duct passes for- 

 ward and opens close to the duct of the infra-orbital gland. The sub- 

 maxillary gland (Fig. 125, s.mx.gl), is a reddish, ovoidal, compact 

 body situated inside the angle of the lower jaw and near the middle 

 line, somewhat anterior to the larynx; its duct runs forward to open 

 into the mouth a short distance behind the lower incisors. The sub- 

 lingual gland (si. gl) is an elongated structure situated on the inner 

 bide of the mandible, and having several ducts opening independently 

 into the mouth. 



The oral cavity is continued backwards .as thu pharynx 

 {ph) : this begins at the velum palati, above which it ex- 

 tends forwards as the naso-pharynx (n. pK) ; the latter is con- 

 tinuous with the passage of the internal nostrils, and'iiito 

 it open the Eustachian tubes {(^s, compare pp. 17 and 45). 

 On the floor of the pharynx, behind the base of the tongue, 

 is the glottis, which leads into the larynx and is guarded- in 

 front by an elastic, leaf like, cartilaginous flap, the epiglottis 

 {epg) ; this projects upwards towards the velum palati and 

 is capable of being pressed backwards over the glottis during 

 the passage of food from the mouth to the gullet. 



The gullet (^igs. 125 and 127, «j)is a narrow but dilatable 

 tube which passes backwards along the neck and through 

 the thorax, entering the abdomen through an aperture 

 in the diaphragm and then opening into the stomach 

 {py. st, cd. st), a wide, curved sac, elongated transversely 

 and greatly dilated at the cardiac end, which lies towards the 



