ILLUSTRATIONS 



109. — Ears of Fcetal Macaque (A) and of a Six 



Months' Human Fcetus (B) . . . 212 



(From Plate, after Schwalbe, Allgem. Zool., Gustav 

 Fischer.) 



110. — External Ears of Anthropoids and Men 213 



(After Keith.) 



A. Chimpanzee. 



B. "Small chimpanzee type" (human). 



C. "Chimpanzee type" (human). 



D. Orang. 



E. "Orang type" (human). 



F. Gorilla. 



G. Gibbon. 



H. Lemuroid (Nycticebus). 



111. — The Middle Ear of Man, Showing the 



Auditory Ossicles . . . . .216 



(After Cunningham.) 



A. View of the left tympanum (drum membrane) 

 from the inner side. The ossicles are cut away except 

 the handle of the malleus, which is inserted into the 

 drum membrane. 



B. The same, showing the three ossicles in place. 



112. — Relations of the Parts of the Middle Ear 



in an Extinct Mammal-like Reptile . 217 



A, Side view of back part of lower jaw of Permo- 

 cynodon, a cynodont reptile from the Permian of Rus- 

 sia. (Mainly after Sushkin.) 



The broken line indicates the position of the pouch 

 from the tubo-tympanal cavity as inferred by Watson 

 and Sushkin. 



B. Rear view of the skull of Permocynodon, show- 

 ing the perforate stapes in position. (After Sushkin.) 



The broken lines (added by the present author) 

 indicate his interpretation of the position of the middle- 

 ear chamber and of the tympanic membrane. The 

 existence of an extra columella, as in primitive rep- 



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