viii Table of Contents 



CHAPTER V 

 SENSORY DISCRIMINATION: THE CHEMICAL SENSE 



PAGES 



18. The Chemical Sense in Ccelenterates. 19. The 

 Chemical Sense in Flatworms. 20. The Chemical 

 Sense in Annelids. 21. The Chemical Sense in Mol- 

 lusks. 22. The Chemical Sense in Echinoderms. 

 23. The Chemical Sense in Crustacea. 24. The 

 Chemical Sense in Arachnida. 25. The Chemical 

 Sense in Insects. 26. How Ants find Food. 27. How 

 Ants find the Way Home. 28. How Ants " recognize " 

 Nest Mates. 29. How Bees are attracted to Flowers. 

 30. How Bees find the Hive. 31. How Bees "rec- 

 ognize" Nest Mates. 32. The Chemical Sense in 

 Vertebrates 67-105 



CHAPTER VI 



SENSORY DISCRIMINATION: HEARING 



33. Hearing in Lower Invertebrates. 34. Hearing 

 in Crustacea. 35. Hearing in Spiders. 36. Hear- 

 ing in Insects. 37. Hearing in Fishes. 38. Hear- 

 ing in Amphibia. 39. Hearing in Higher Vertebrates 106-119 



CHAPTER VII 



SENSORY DISCRIMINATION: VISION 



40. Some Problems connected with Vision. 41. Vis- 

 ion in Protozoa. 42. Vision in Coelenterates. 

 43. Vision in Planarians. 44. Vision in Annelids. 

 45. Vision in Mollusks. 46. Vision in Echino- 

 derms. 47. Vision in Crustacea. 48. Vision in 

 Spiders. 49. Vision in Insects. 50. Vision in 

 Amphioxus and in Fish. 51. Vision in Amphibia. 

 52. Vision in Other Vertebrates .... 120-147 



