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CONTENTS 



CHAPTEK I. 



FACE 



Introductory remarks— Difficulty of the subject — The life of a 

 cell — Possible modes of origin of sense-organs — Origin of 

 eye and ear — The sense of touch — The organs of touch — 

 Nerves of touch — Sense of temperature — Cold points — Heat 

 points — Pressure-points— Organs of touch among lower 

 animals — Medusae — Aunclides— Mollusca — Crustacea — In- 

 sects— Sense-hairs — Tactile hairs ... ... ... 1 



CHAPTER II. 



The sense of taste — Taste-organs of man — Mammalia — Birds — 

 Reptiles — Taste-organs of the lower animals — Crustacea — 

 Insects — Sense of taste in insects— Organs of taste in 

 insects — The bee — Humble bee — "Wasp — Fly — Individual 

 differences ... ... ... ... ... ... 19 



CHAPTER III. 



The sense of smell — Protozoa and Coelenterata — Worms — Mollusca 

 — Insects— Seat of the sense of smell— Different theories as 

 to the seat of the sense of smell in Insects — Experiments 

 with Dinetus — Hydaticus — Silpha — Stag-beetle — Ants — 

 Seat of the sense of smell partly in the palpi, partly in 

 antennae — Organs of smell — Leydig's olfactory cones — 

 Organs of smell in Crustacea — Centipedes — Olfactory 

 cones in insects — Olfactory hairs — Olfactory pits — Ol- 

 factory organs of fly — Antenna of Ichneumon — Olfactory 

 organs of wasp — Antenual organs of insects — Complex 

 structure of the antennae— Various uses of antennae ... 32 



