PAGE Definition of mind--The correlation of physiology, morphology, and psychology--The presence of nerve-elements in _monera_--Conscious and unconscious mind--Unconscious ("vegetative") mind in the jelly-fish--Anatomy, physiology, and psychology of the jelly-fish --The origin of conscious mind. 1 CHAPTER I THE SENSES IN THE LOWER ANIMALS The sense of touch--The senses of taste and smell--Actinophryans having taste--The sense of sight--Modification of sight organs by surroundings --Sight in Actinophryans--Blind fish sensitive to light--Blind spiders --Blind man--Primitive eyes in _Cymothoe_--In the jelly-fish, sea-urchin, _Alciope_, _Myrianida_--The sight organs of the snail--Power of vision in the snail--Eyes of crayfish--Compound eyes--Vision in "whirligig beetle"--In _Periophthalmus_--In _Onchidium_--In _Calotis_--Organs of audition--In _Lepidoptera_--_Hymenoptera_--_Orthoptera_--_Diptera_ --_Hemiptera_--_Dyticus marginalis_--_Corydalus_--Ears of grasshopper and cricket--Of the "red-legged locust"--Of flies--Of gnats--Auditory vesicles of horse-fly--Ears of butterflies--Cerambyx beetle--Long-horned beetle--_Cicindelidæ_--_Carabidæ_. 7 CHAPTER II CONSCIOUS DETERMINATION Definition--How conscious determination is evolved from the senses--The presence of nerve-tissue in _Stentor polymorphus_--The properties of nerve-tissue--Romanes' experiment with anemone--Action of stimuli on nerve-tissue--Reflection--Origin of consciousness--Time element in consciousness--Conscious determination in _Stentor polymorphus_--In _Actinophrys_--In _Amoeba_--In _Medusa_--In a water-louse--In a garden snail--In the angle-worm--In oysters--In a ground wasp. 39 CHAPTER III MEMORY Discussed under four heads, viz. _Memory of Locality_ (_Surroundings_), _Memory of Friends_ (_Kin_), _Memory of Strangers_ (_Other animals not kin_), and _Memory of Events_ (_Education_, _Happenings_, etc.)--Memory of locality in _Actinophrys_--In the snail--In the ant--In sand wasps--In beetles--In reptiles--_Memory of Friends_--In ants --Experiments with ants, _Lasius flavus_, _Lasius niger_, and _Myrmica ruginodis_--Memory of kin in wasps and bees--Experiments --_Memory of Strangers_ (_Animals other than kin_)--Recognition of enemies--By bumblebees--Memory of individuals not enemies--By the toad--By the spider--By ants--By snakes--By chameleons--By birds --By cattle--By dogs--By monkeys--_Memory of Events_ (_Education_, etc.) --In the wasp--In fleas--In the toad--In other insects. 60 CHAPTER IV THE EMOTIONS