S SAND-WASP, memory of locality in, 62; author's experiments with, 63. SARCOPTES HOMINIS, death-feigning in, 209. SATIN BIRD, æstheticism in the male, 128; author's observations of, 128. SEA-URCHIN, eyes of, 16. SNAIL, eyes of, 19; visual powers of, 19; courtship of, 20; location of sense of direction in, 194; author's experiments with, 194; author's experiments in demonstrating homing sense in the, 194. SNAKE, love of young in, 140; author's experiment in testing parental affection of, 140; sense of direction and "homing instinct" in, 198; author's observations of "homing instinct" in, 198. SOLE, the origin of unilateral eyes in the, 9. SONG-SPARROW, memory of individuals in, 77; parental affection in, 143. SPANIEL, a laughing, 89. SPIDER, memory in, 72; recognition of individuals by, 73; love of music in the, 108; author's experiments with piano on, 108; author's experiments with pipe organ on, 109; Reclain's observations on the love of music in, 109; decorative instinct present in, 110; peculiar web spun by, 110; parental affection in, 135; author's experiment in testing parental love of, 135; use of implement (pebble anchor) by, 222. SQUIRREL, memory in the, 70. STENTOR POLYMORPHUS, nervous system of, 46; observations of and experiments with, 47; conscious determination in, 47; ganglia of, 47. STRONGALOGNATHUS, degeneration caused by the habit of slave-making in, 155, 156, 157.