xviii LIST OF ILLUSTRATIONS 



FIG PAGE 



20. Diagram illustrating Circulation of Blood .... 70 



21. (a) Bird's Heart, (b) Human Heart, opened to show 



Valves 73 



22. {a) and (b) Red and White Corpuscles of Man, (c) 



and (d) Red Corpuscles of Humming Bird and 

 Ostrich, (e) Amozb^e 75 



23. Air-sacks— Diagram 80 



24. Section of (a) Femur of Ostrich, (b) of Skull of 



Carinate Bird 82 



25 Diaphragm of Duck 85 



26. Diagram illustrating Process of Breathing .... 87 



27. Do. do. do. .... 91 



28. Humerus of (p) Skua, (b) Hornbill, (c) Eagle .... 111 



29. Two Cubes 113 



30. Brain of Bird 118 



31. Eye of (a) Man, (b) Typical Bird, (<■) Owl 122 



32. Section of Retina of Bird 125 



33. (a) Human Ear, (b) Ear of Owl, (c) of Thrush ... 132 



34. Syrinx of Raven 137 



35. Convolutions of Crane's Trachea 140 



36. Striated and Unstriated Muscle 142 



37. (a) Feather carrying Nestling Down-feather, (b) 



Nestling "Down" of Thrush, (c) of Pigeon, (d) 

 Thread Feather 145 



38. Contour Feathers, (a) Plumelike, (b) Flight-Feather 147 



39. Barbules and Barbicels to illustrate interlock- 



ing 148 



40. Cassowary's Feather 150 



41. Illustration of Development of Feather 151 



42. Beak of (i) Falcon, (2) Duck 162 



43. Foot of (i) Woodpecker, (2) Grebe . . . . • .... 165 



44. Flexor Tendons of Toes of {a) Fowl, {b) Passerine 



Bird 167 



