ADDITIONAL PACTS ABOUT BIRDS. 113 



46. What muscle moves the wing down? 



47. What is a tendon? 



48. To what boue is the tendon of the pectorafis minor 



attached? At what place on the bone is it 

 attached? 



49. Has the pigeon a diaphragm ? 



50. How many ribs? 



51. What difference between the bones of the neck 



and the bones of the back? 



52. What is the pericardium? 



5S. What is the principal artery leaving the heart? 



54. From which end of the heart does it go? 



55. In what direction does it turn? 



56. What is the first branch of the aorta? 



57. To what organ does the left subclavian artery 



carry blood? 



58. What is the first branch it gives off? 



59. What is the second branch of the aorta? 



60. To what does the right subclavian carry blood? 



61. What is its first branch? 



62. To what other organ does the aorta carry blood? 



63. What veins bring blood back to the heart? 



64. What tubes open into the cloaca? 



65. How many chambers in the heart? 



66. What and where is the occipital condyle? 



67. What and where is the quadrate bone? 



68. Name all the parts of an egg. 



69. Name all the parts of a feather. 



Additional Facts About Birds. 



Birds are distinguished from all other animals by 

 being almost completely covered with feathers. We 

 can see, however, that on some birds the tarsus is 

 covered with scales instead of feathers. So it seems 

 quite evident that in some way the feathers take the 

 place of scales. Feathers are therefore homologous 



