( 2 68 ) 



TABLE XXXIII. 



Systematic Survey of the Development of the Human Ear. 



I. Survey of the parts of the Internal Ear. (Apparatus perceptive of sound.) 



Products of the < 



Horn-plate 



1. Stalk of the primary 1. Aqueduct of the Aquceductus vestibuli 



ear- vesicle vestibule (Due- s. Recessus labyrinthi 



tus endolym- 

 phaticus) 



2, 3. Upper part of the 2. Ear-pouch Utriculus 



primary ear-vesicle 3. Three semi-circu- Canales semi-circu- 



lar, or curved 

 canals 



4, 5. Lower part of the 4. Ear-sac 



primary ear-vesicle 5. "The snail" 



lares 



Sacculus 

 Cochlea 



B. 



Products of the 



Head-plate 



1 6. Auditory nerve 6. Auditory nerve Nervus acusticus 



7. Bony covering of the 7. Osseous labyrinth Labyrinthus osseus 



membranous laby- 

 rinth 



8. Bony covering of the 8. " The stony bone " Os petrosum 

 \ whole internal ear 



II. Survey of the parts of the Intermediate and External Ear. (Apparatus for the 



conveyance of sound.) 



Products of the 

 first 



Gill-opening 



/ 



D. 



Products of the 

 first two 



Gill-arches 



E. 



Product of the 



Head-plate 



Product of the 

 Skin-covering 



f 9. 

 10. 



11, 



,12. 

 13. 

 14. 



/l5. 



I 



16. 



Inner part of the first 

 gill-opening 



Central part of the first 

 gill-opening 



Closed part of the first 

 gill-opening 



Upper part of the 

 second gill-arch 



Upper part of the first 

 gill-arch 



Central part of the first 

 gill-arch 



Tympanic circle 

 (Anmilus tympanicus) 



Circular membranous 

 fold at the closed part 

 of the first gill- 

 opening 



9. Eustachian tube Tuba Eustachii 



10. Tympanic cavity Cavum tympani 



(Interior of the 

 drum) 



11. Tympanic mem- Membrana tympani 



brane (Head of 

 the drum) 



12. Stirrup (First Stapes 



bonelet of the 

 ear) 



13. Anvil (Second Incus 



bonelet of the 

 ear) 



14. Hammer (Third Malleus 



bonelet of the 

 ear) 



15. Bony outer audi- Meatus auditorius 



tory passage osseus 



16. Ear-shell 



Concha auris 



17. Rudimentary ear- Musculi concha? 

 muscles 



