n the, 89;
use of missiles by, 222.

OX, homing sense in the, 199, 200.

OYSTER, eyes of, 16.

P

PAPILIONINAE, length of life in tropical, 137.

PERCH, love of offspring in the white, 138.

PERIOPHTHALMUS, habitat of, 25;
peculiar mode of life of, 25;
eyes of, 25;
food of, 26.

PIGEON, love of music in the, 122;
Lockman's account of a music-loving, 122;
musical discrimination in, 122.

PIPE-FISH, parental affection in the, 139;
Risso's observations, 139.

PLAICE, the origin of unilateral eyes in the, 9;
absence of color-changing faculty in blind, 188;
Pouchet's demonstration of the color-changing function of the
sympathetic nerves in, 189.

PODURA, _F. fusca_ and _F. rufescens_ make pets of, 126;
author's observations of, 126.

POLYERGUS, lowering tendency of slavery shown by, 155, 156.

PRIONUS, author's experiments in locating organs of hearing in, 36.

Q

QUAIL, domesticated, 111;
love of caresses in, 111;
love of instrumental music in, 111;
fondness for the singing voice in, 112.

R

RAT, fondness for instrumental music in, 116;
power of musical discrimination in, 116.

REASON, definition of, 147;
difference between instinct and, 148.

RHIZOPOD, sense of direction in, 48;
Carter's observations of, 49;
memory in, 60.

ROBIN, homing sense in, 199.

S

SAND-WASP, memory of locality in, 62;
author's experiments with, 63.

SARCOPTES HOMINIS, death-feigning in, 209.

SATIN BIRD, aestheticism 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;
pare