50 STUDIES IN" COMPARATIVE ANATOMY. 



The pharyngeal openings of the Eustachian tubes lie in the 

 lateral walls of this part of the pharynx, about an inch above 

 the hamular pterygoid process, and a little above the level of the 

 hard palate. The orifices are large enough to admit the little 

 finger. In its lower part each tube is almost entirely membran- 

 ous. It runs upwards and a little outwards, and may be 

 explored by a probe for 7 inches. We have been unwilling 

 to destroy the surrounding parts for the sake of tracing the tube 

 further. According to Camper's figures (pi. xiii. figs. 7, 8), the 

 bony tube is about 2 inches long and the cartilaginous tube 

 over an inch. The same author describes and figures an open- 

 ing from the upper part of the cartilaginous tube into the 

 nasal passage. We find no corresponding opening in the soft 

 parts. 



The common aperture of the posterior nares occupies a 

 triangular space 4^ inches high and 2 inches wide. The hind 

 edge of the septum is very thin, and deeply concave above. 



Muscles of the Pharynx. 



Constrictor pharyngis arises on each side from the thyro-hyal, 

 from the posterior margin of the thyroid cartilage, and from the 

 cricoid cartilage below the arytsenoid facet. The fibres pass 

 round the tube of the pharynx, and blend along the middle Kne 

 behind. The uppermost (or anterior) fibres form a tolerably 

 distinct bundle. The lower fibres curve upwards so as to leave 

 a triangular gap, which is filled by a tapering median bundle of 

 the longitudinal oesophageal fibres. 



C. and L.— 261, fig. 1 {s\ £-, z^). 



Stylo-pharyngeus arises from the internal surface of the 

 anterior branch of the stylo-hyal, close to its origin. The 

 muscle passes downwards along the side of the pharynx and is 

 there inserted. 



C. and L.— 261, fig. 1 (v^). 



Palato-pharyngens is largely developed. It arises from the 

 palate and descends to the pharynx, forming a considerable part 

 both of the soft palate and the velum palati. It is inserted 

 laterally on the inner surface of the pharyngeal wall. 



A symmetrical venous plexus, which arises by free communi- 

 cations between the internal jugular, internal maxillary, and 



