6. Tracks of dancer (After Alexander and Kreidl)

7. The inner ear of the rabbit (Retzius)

8. The membranous labyrinth of the ear of the dancer (After Rawitz)

9. Same

10. Same

it. Model of the ear of the dancer (After Baginsky)

12. Ear of the dancer (After Kishi)

13. Ear of the dancer (After Kishi)

14. Discrimination box

15. Ground plan of discrimination box

16. Nendel's gray papers

17. Weber's law apparatus

18. Food-box apparatus

19. Waugh's food-box apparatus

20. Color discrimination apparatus