147 Cuckoo-Spit 147     Photo: G. P. Duffus. Chimpanzee, Sitting 156     Photo: New York Zoological Park. Chimpanzee, Illustrating Walking Powers 156     Photo: New York Zoological Park. Surface View of the Brains of Man and Chimpanzee 157 Side-View of Chimpanzee's Head 157     Photo: New York Zoological Park. Profile View of Head of Pithecanthropus, the Java Ape-Man, Reconstructed from the Skull-Cap 157     After a model by J. H. McGregor. The Flipper of a Whale and the Hand of a Man 157 The Gorilla, Inhabiting the Forest Tract of the Gaboon in Africa (Coloured Illustration) 158 "Darwin's Point" on Human Ear 160 Professor Sir Arthur Keith, M.D., LL.D., F.R.S. 161     Photo: J. Russell & Sons. Skeletons of the Gibbon, Orang, Chimpanzee, Gorilla, Man 161     After T. H. Huxley (by permission of Messrs. Macmillan). Side-View of Skull of Man and Gorilla 164 The Skull and Brain-Case of Pithecanthropus, the Java Ape-Man, as Restored by J. H. McGregor from the Scanty Remains 164 Suggested Genealogical Tree of Man and Anthropoid Apes 165 The Gibbon is Lower than the Other Apes as Regards its Skull and Dentition, but it is highly Specialized in the Adaptation of its Limbs to Arboreal Life 166     Photo: New York Zoological Park. The Orang Has a High Rounded Skull and a Long Face 166     Photo: New York Zoological Park. Comparisons of the Skeletons of Horse and Man 167     Photo: British Museum (Natural History). A Reconstruction of the Java Man (Coloured Illustration) 168 Profile View of the Head of Pithecanthropus, the Java Ape-Man—an Early Offshoot from the Main Line of Man's Ascent 170     After a model by J. H. McGregor. Piltdown Skull 170     From the reconstruction by J. H. McGregor. Sand-Pit at Mauer, near Heidelberg: Discovery Site of the Jaw of Heidelberg Man 171     Reproduced by permission from Osborn's Men of the Old Stone Age. Paintings on the Roof of the Altamira Cave in Northern Spain, Showing a Bison and a Galloping Boar (Coloured Illustration) 172 Piltdown Man, Preceding Neanderthal Man, Perhaps 100,000 to 150,000 Years Ago 174     After the restoration modelled by J. H. McGregor. The Neanderthal Man of La Chapelle-aux-Saints 175     After the restoration modelled by J. H. McGregor. Restoration by A. Forestier of the Rhodesian Man whose Skull was Discovered in 1921 176-177 Side View of a Prehistoric Human Skull Discovered in 1921 in Broken Hill Cave, Northern Rhodesia 178     Photo: British Museum (Natural History). A Cromagnon Man or Cromagnard, Representative of a Strong Artistic Race Living in the South of France in the Upper Pleistocene, Perhaps 25,000 Years Ago 178     After the restoration modelled by J. H. McGregor. Photograph Showing a Narrow Passage in the Cavern of Font-de-Gaume on the Beune 179     Reproduced by permission from Osborn's Men of the Old Stone Age. A Mammoth Drawn on the Wall of the Font-de-Gaume Cavern 179 A Grazing Bison, Delicately and Carefully Drawn, Engraved on a Wall of the Altamira Cave, Northern Spain 179 Photograph of a Median Section through the Shell of the Pearly Nautilus 186 Photograph of the Entire Shell of the Pearly Nautilus 186 Nautilus 186 Shoebill 187     Photo: W. S. Berridge. The Walking-Fish or Mud-Skipper (Periophthalmus), Common at the Mouths of Rivers in Tropical Africa, Asia, and North-West Australia 190 The Australian More-Pork or Podargus 190     Photo: The Times. Pelican's Bill, Adapted for Catching and Storing Fishes 191 Spoonbill's Bill, Adapted for Sifting the Mud and Catching the Small Animals, e.g. Fishes, Crustaceans, Insect Larvæ, which Live there 191 Avocet's Bill, Adapted for a Curious Sideways Scooping in the Shore-Pools and Catching Small Animals 191 Hornbill's Bill, Adapted for Excavating a Nest in a Tree, and Also for Seizing and Breaking Diverse Forms of Food, from Mammals to Tortoises, from Roots to Fruits 191 Falcon's Bill, Adapted for Seizing, Killing, and Tearing Small Mammals and Birds 191 Puffin's Bill, Adapted for Catching Small Fishes near the Surface of the Sea, and for Holding them when Caught and Carrying them to the Nest 191 Life-History of a Frog 192 Hind-Leg of Whirligig Beetle which has Become Beautifully Modified for Aquatic Locomotion 192     Photo: J. J. Ward, F.E.S. The Big Robber-Crab (Birgus Latro), that Climbs the Coconut Palm and Breaks off the Nuts 193