vi Illustrations 



FACING 

 PACK 



PHOTO OF STATUE TAKEN THROUGH THE LENSES OP THE FLY'S CORNEA . 307 



SURFACE VIEW OF THE COMPOUND EYE OF A FLY, SHOWING THE NUMER- 

 OUS HEXAGONAL FACETS ON THE TRANSPARENT CORNEA . . . 308 



SURFACE VIEW OF THE SAME EYE, SHOWING THE CORNEAL OR OUTER 



LENSES FITTING AGAINST THE HEXAGONAL FACETS OR FRAMES . . 308 



PART OF THE WING OF A WALL-BUTTERFLY 309 



Photo: J. J. Ward. 



CROSS-SECTION OF THE SPINE OF A SEA-URCHIN (Cidaris metularia), 



MAGNIFIED SEVERAL DIAMETERS ..... . 309 



Photo: J. J. Ward. 



THUMB-PRINT IN WAX . . . . . . . . .310 



Reproduced by courtesy of Messrs. F. Davidson & Co. 



FEET OF THE JUMPING-LEGS OF THE COMMON FLEA . . .311 



Photo: J. J. Ward. 



ONE OF THE FORE-LEGS OF THE MOLE CRICKET (GRYLLOTALPA) . . 312 

 Photo: J. J. Ward. 



A PIECE OF HIGH-SPEED STEEL SEEN UNDER THE HIGH MAGNIFICA- 

 TION OF 1500 DIAMETERS . . . . . .313 

 Reproduced by courtesy of Messrs. F. Davidson & Co. 



SCALE FROM A GOLD-FISH .... ... 313 



Photo: J. J. Ward. 



FOOT OF A HOUSE-FLY . . . . . . . .318 



Photo: J. J. Ward. 



THE BEAUTIFUL PATTERN ON THE MICROSCOPIC FLINTY SHELL OF A 

 DIATOM (Arachnoidiscus ehrenbergt), A KIND OF UNICELLULAR 

 PLANT .. ..... ...318 



Photo: J. J. Ward. 



VERTICAL LONGITUDINAL SECTION (AFTER OWEN) OF A HUMAN MOLAR 



TOOTH .319 



A PORTION OF THE CEsoPHAGus OR GULLET LAID OPEN TO SHOW A BOLUS 

 OF FOOD PASSING DOWN ..... 



Reproduced by permission from Keith's The Engines of the Human Body 

 (Williams and Norgate). 



DR. JENNER (1749-1823) INOCULATING HIS OWN SON: THE STATUE BY 



J. MONTEVERDE AT GENOA (Coloured Illustration) . 322 



Photo: Alinari. 



