DROSERA ROTUNDIFOLIA, insectivorous, 208. DUCK, friendship between bantam cock and, 78; hawk attacked and killed by, 78; sense of direction in, 199. DYTICUS MARGINALIS, auditory rods of, 30; death-feigning in a fresh-water annelid when approached by, 204. E EAGLE, recognition of individuals by, 76. EAR, Dyticus, 30; corydalis, 30; grasshopper's, 31; Tabanus, 34. EARWIG, method of incubation practised by, 105; care of young by, 105; M. Geer's experiment with, 105; love of offspring in, 106; author's experiments in testing parental affection in the, 136. ECITON HAMATA, ants of the same species rescue an imprisoned, 100; Belt's experiments in testing the sympathy of, 101. ELEPHANT, abstract ideation in the, 217; Conklin's testimony as to abstract ideation in, 218; mud used to stop bullet holes by, 220; a branch of a bush used as a fan by, 221. EPIPONE SPINIPES, method of supplying larva with fresh food used by, 104; differentiation in the amount of food for male and female grub, 104. ETIOLATION, definition of, 184, 185. EUPLOCINÆ, length of life in tropical, 137. EYE, flounder's, 9; plaice's, 9; sole's, 9; mole's, 10; fresh-water _Cymothoe's_, 13; OEquorea's, 15; sea-urchin's, 16; oyster's, 17; _Alciope's_, 17; snail's, 19; crayfish's, 21; _Gyrinus'_, 23; _Periophthalmus'_, 25; _Onchidium's_, 26; calotis', 27. F FISH, phosphorescent and pigmented, 13; parental affection in, 138; sense of direction in, 200. FLEA, memory in the, 86; dancing and military evolutions by, 86; method of educating the, 87. FLOUNDER, the origin of unilateral eyes in, 9. FORMICA FUSCA, sympathy in, 100; species of _Podura_ domesticated by, 126. FORMICA RUFA, sympathy evinced by, 102. FORMICA RUFESCENS, pet beetles in the nest of, 126. FORMICA SANGUINEA, slave-making habit in, 155; sympathy evinced by, 102; Lubbock's observations of a sick, 102. FROG, tinctumutation in the, 182; chromatophores of, 182; Heincke's observations, 183; location of color-changing sense in, 190. G GADFLY, selection of suitable spot for oviposition by, 103. GILT CATFISH, _gyropeltes_ make the toilet of, 130; color-changing in, 183; author's experiments on the color-changing function of, 191. GOBIUS RUTHENSPARRI, tinctumutation in, 183. GOGGLE-EYE PERCH, love of offspring in, 138; homing sense in, 200. GOOSE, homing sense in the, 199. GORILLA, use of cudgel by, 222. GRASSHOPPER, ears of, 30. GYRINUS, indifference to seasons shown by, 23; eyes of, 24. GYROPELTES, health of gilt catfish dependent on, 130. H HELICONIDÆ, length of life in, 138. HELIX POMATIA, love of amusement in, 123; author's observations, 124. HEMIPTERA, organs of audition in, 29. HOG, friendship between a dog and a, 81.