vi CONTENTS 
CHAPTER LVIII—SENSE-ORGANS OF BACKBONELESS ANI- 
MALS (INVERTEBRATA) AND BACKBONED ANIMALS (VERTE- 
BRATA) 
The Nature and Uses of Sense-Organs; Organic Sensations; Special Senses - - 
ToucH—General Nature: Haptic and Thermal Sensations; Tactile Organs of 
Zoophytes, Annelids, Arthropods, and Vertebrates. Pacinian Bodies and the 
Pressure-Sense. Organs of Active Touch - - - 
TasTE—General Nature: Gustatory Organs of Annelids, Insects, Molluscs, and 
Vertebrates; Taste-Buds - - 
SMELL—General Nature: Distance-Senses (Telesthetic Senses); Olfactory Organs 
of Arthropods, Molluscs, and Vertebrates - - - - - 
BALANCE AND HEARING—General Nature a = Z 
Balancing Organs of Jelly-Fishes (Hydrozoa)—Otocysts and Tentaculo- 
cysts and their Uses - - 
Balancing Organs in Segmented Worms (Annelida)—Earth- HE, Oto- 
cysts of Lug-Worms (Avenicola) - 
Balancing Organs in Molluscs (Mollusca)—Otocysts of Bivalves (Lamedit- 
branchia), Snails and Slugs (Gastropoda), and Head-footed Molluscs 
(Cephalopoda) 
Organs of Balance and Hearing in Crustaceans (Crustacea)—Otocysts of 
Lobsters, Prawns, Shrimps, and Crabs; Otocysts in Tail of Opossum 
Shrimp (JZyszs); Sound-producing Crustaceans—Rock-Lobster (Pa/z- 
nurus), Musical Strand-Crab (Ocypoda macrocera), Squeaker Crab 
(Psopheticus stridulans) - 
Organs of Balance and Hearing in Insects ({nsecta)—Chordotonal Organs: 
Musical Organs of Grasshoppers, Green Grasshoppers, and Crickets 
Organs of Balance and Hearing in Backboned Animals (Vertebrata)— 
Otocyst in the Brain of Larval Ascidians (Uvochorda); Structure 
and Uses of the Auditory Organs of Aquatic- and Land-Vertebrates - 
SIGHT—Shin-Seeing (Dermatoptic Vision) of Earth-Worms and Bivalve Molluscs - 
Direction-E-yes—Euglena, Jelly-Fishes (Hydrozoa), Star-Fishes and Sea- 
Urchins (Echinodermata), Segmented Worms (Annelida), Arrow- 
Worms (Chetognatha), and Limpet (Patella) - - 
Picture-Eyes—Compound Eyes of Crustaceans and Insects. Camera 
Eyes of Annelids, Arthropods, and Molluscs. Camera Eyes of Verte- 
brates—Structure and Development; Visual Organs of the Double- 
Eyes (Anableps) ; Pineal Eyes of certain Reptiles - - 
ANIMAL INSTINCT AND INTELLIGENCE 
CHAPTER LIX.—GENERAL PRINCIPLES—INSTINCT AND IN- 
TELLIGENCE IN HIGHER BACKBONELESS ANIMALS 
(INVERTEBRATA) AND BACKBONED ANIMALS (VERTEBRATA) 
GENERAL PRINCIPLES—Reflex Action, Instinct, Intelligence, Reason - 
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