306 



COMPARATIVE ANATOMY 



cartilaginous auditory passage, with which it is continuous. In its 

 formation and further development, the dermal musculature 

 primarily plays the most important part. 



In the higher Mammals the pinna and the cartilaginous part of 



m.a.' 



FIG. 225. THE PINNA OF VARIOUS PRIMATES. 



In A, the shaded portion (6) represents the zone of the auditory eminences of the 

 embryo, the unshaded that of the later-formed auditory fold. B, Man, 

 Baboon and Ox, drawn to the same scale and superposed : s', s", s, spiria or 

 tip of the ear. " 

 pithecus, with 

 as follows i) 



m.t', inconstant muscle, extending from the tragicusto the margin of the 

 helix ; m.h', helicis major; m.h", helicis minor ; s, tip of the ear rolled over. 



A-D, after Schwalbe ; E, after Henle. 



the external meatus (here also continuous with one another) arise 

 from a series of rounded eminences on the first and second visceral 



