LIST OF ILLUSTRATIONS. 



HtiMAN Hair 3 



Hog's Bristle 6 



Fibre of Sheep's Wool 8 



Hair of Cat 9 



Hairs of Mole 9 



Hair of Sable 10 



Hair of Mouse 11 



Tip of Small Hair of Mouse 11 



Hair of Bat 11 



Hair of Indian Bat 12 



Tip OF Hair of Dermestes 15 



Barb of Clothing Feather of Fowl 16 



Barb from Goose-quill 17 



Scales of Perch 19 



Scales of Goldfish 21 



Scale of Flounder 23 



Scales of Pike 24 



Sficula OF Goldfish Scale 25 



Blood Disks 31 



Circulation in Frog's Foot 35 



Perophora 36 



Cuttle-Shell 45 



Section of Nacre from Pearl Oyster 48 



Tongue of Trochus 54 



Structure of Eye in Snail 62 



Leafy Sea-mat 70 



Doubling and Hooks in a Bee's Wing 83 



