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THE EVOLUTION OF MAN. 



Senur^ngant. 



o6flM-fKr0M. 



Sem^/uneticma. 



A* Sense-organs in 

 which the ter- 

 minal expansions 

 of the nerves are* 

 distributed in the 

 outer akin-oorer. 

 ing. 



B. Sense-organs in 

 which . the ter- 

 minal expansions 

 of the nerves are 

 distributed over 

 inverted grooves 

 of the outer skin. 

 covering. 



0. Sense-organs in 

 which the ter- 

 minal expansions 

 of the nerves are 

 distributed over-' 

 vesicles sepa- 

 rated from the 

 external skin. 

 ooTering. 



I. Skin-covering 

 (outer skin, or 

 epidermis, and 

 leather - skin, 

 or corivm) 



n. External 

 sexual parts 

 (penis and eli- 

 toria) 



m. Muoousmem- 

 brane of the 

 mouth - cavity 

 (tongue and 

 palate) 



IV. Mucous mem- 

 brane of the 

 nose-cavity 



V. Bye 

 VI. Ear 



I. Skin nerves ) Sense of pressure 

 (nervi cutcmei) i Sense of warmth 



II. Sexual nerves 3. Sexual senM 

 (nervi pudendi) 



m. Taste nerve 

 (nervus gloaso- 

 pharyngev>8) 



TV. Olfactory 

 nerve 

 (n. olfactorius) 



4. SeoBO of taste 



6. Sense of smeU 



V. Sight nerve 6. Sense of sight 

 {n. opticus) 



VI. Ear-nerve 7. Sense of hear- 

 (n. acousticus) ing 



Of the developmental history of the lower organs of 

 sense I have but little to say. The development of the skin- 

 covering, which is the organ of the sense of pressure (sense 

 of touch) and of warmth, we have already traced (p. 209). 

 I need only add that in the leather skin (corium) of Man, 

 as of aU higher Vertebrates, innumerable microscopic sense- 

 organs develop, the direct relations of which to the sensa- 

 tions of pressure or resistance, of warmth and of cold, are 

 not yet ascertained. These organs, in or upon which the 

 sensitive skin-nerves terminate, are the so-caUed "touch 

 bodies " and the " Pacinian bodies/' named after their dis- 



