73

OKAPI AND GIRAFFE (_Coloured Illustration_) 74

DIAGRAM OF A SIMPLE REFLEX ARC IN A BACKBONELESS ANIMAL
LIKE AN EARTHWORM 76

THE YUCCA MOTH 76
Photo: British Museum (Natural History).

INCLINED PLANE OF ANIMAL BEHAVIOUR 76

VENUS' FLY-TRAP 77
Photo: J. J. Ward, F.E.S.

A SPIDER SUNNING HER EGGS 77
Reproduced by permission from _The Wonders of Instinct_ by
J. H. Fabre.

THE HOATZIN INHABITS BRITISH GUIANA 82

PERIPATUS 83
Photograph, from the British Museum (Natural History), of a
drawing by Mr. E. Wilson.

ROCK KANGAROO CARRYING ITS YOUNG IN A POUCH 83
Photo: W. S. Berridge, F.Z.S.

PROFESSOR THOMAS HENRY HUXLEY (1825-95) 86
Photo: Rischgitz.

BARON CUVIER, 1769-1832 86

AN ILLUSTRATION SHOWING VARIOUS METHODS OF FLYING AND
SWOOPING 87

ANIMALS OF THE CAMBRIAN PERIOD 90
From Knipe's _Nebula to Man_.

A TRILOBITE 90
Photo: J. J. Ward, F.E.S.

THE GAMBIAN MUD-FISH, PROTOPTERUS 91
Photo: British Museum (Natural History).

THE ARCHAEOPTERYX 91
After William Leche of Stockholm.

WING OF A BIRD, SHOWING THE ARRANGEMENT OF THE FEATHERS 91

PICTORIAL REPRESENTATION OF STRATA OF THE EARTH'S CRUST,
WITH SUGGESTIONS OF CHARACTERISTIC FOSSILS (_Coloured
Illustration_) 92

FOSSIL OF A PTERODACTYL OR EXTINCT FLYING DRAGON 94
Photo: British Museum (Natural History).

PARIASAURUS: AN EXTINCT VEGETARIAN TRIASSIC REPTILE 94
From Knipe's _Nebula to Man_.

TRICERATOPS: A HUGE EXTINCT REPTILE 95
From Knipe's _Nebula to Man_.

THE DUCKMOLE OR DUCK-BILLED PLATYPUS OF AUSTRALIA 95
Photo: _Daily Mail_.

SKELETON OF AN EXTINCT FLIGHTLESS TOOTHED BIRD, HESPER