LIST OF ILLUSTRATIONS. 



PAGE 



HUMAN HAIR 2 



HOG'S BRISTLE 5 



FIBRE OF SHEEP'S WOOL 7 



HAIR OP CAT 8 



HAIRS OF MOLE 9 



HAIR OF SABLE 9 



HAIR OF MOUSE . 10 



TIP OP SMALL HAIR OF MOUSE 11 



HAIR OF BAT . . . . . . . . . . .11 



HAIR OP INDIAN BAT 12 



TIP OP HAIR OP DERMESTBS . . 14 



BARB OF CLOTHING FEATHER OF FOWL . . . . .15 



BARB FROM GOOSI-QUILL 16 



SCALES OF PERCH 17 



SCALES OF GOLD-FISH 19 



SCALE OF FLOUNDER 21 



SCALES OF PIKE . 23 



SPICULA OF GOLD-FISH'S SCALE 24 



BLOOD DISKS 28 



CIRCULATION' IN FROG'S FOOT 32 



PEROPHORA 33 



CUTTLE-SHELL 41 



SECTION OF NACRE FROM PEARL OYSTER 43 



TONGUE OF TROCHUS 48 



STRUCTURE OF EYE IN SNAIL 54 



LEAFY SEA-MAT 62 



DOUBLING AND HOOKS IN A BEE'S WIXG ..... 74 



SCALES ON A GNAT'S WING . 75 



