ILLUSTRATIONS 



Dancing Mice sniffing and eating .... Frontispiece 



FIGURE PAGE 



1. Color patterns of dancers. Record blanks .... 4 



2. Double cage, with nest-boxes and water dishes . . -17 



3. Double cages in frame .18 



4. Photographs of dancers climbing (After Zoth) ... 43 



5. Tracks of common mouse (After Alexander and Kreidl) . 44 



6. Tracks of dancer (After Alexander and Kreidl) ... 44 



7. The inner ear of the rabbit (Retzius) 54 



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



Rawitz) .......... 56 



9. Same 57 



10. Same 57 



11. Model of the ear of the dancer (After Baginsky) ... 58 



12. Ear of the dancer (After Kishi) 66 



13. Ear of the dancer (After Kishi) 67 



14. Discrimination box ........ 92 



1 5 . Ground plan of discrimination box ..... 93 



1 6. Nendel's gray papers . . . . . . . .115 



17. Weber's law apparatus 119 



1 8. Food-box apparatus . . . . . . .134 



19. Waugh's food-box apparatus 135 



20. Color discrimination apparatus 153 



21. Ground plan of color discrimination apparatus . . .154 

 Cards for form discrimination . . . . . .182 



Labyrinth B 184 



Labyrinth B on electric wires . . . . . .188 



Labyrinth A 211 



26. Curves of habit formation for labyrinth B . . . .217 



27. Plan of labyrinth C, and path records 219 



28. Labyrinth D 222 



29. Curve of learning for white-black discrimination, twenty 



individuals 231 



