60 ELEMENTS OF COMPARATIVE ZOOLOGY. 



Are the feathers essentially alike on all parts of the 

 body ? Are all parts equally well covered ? Pull out a 

 large wing-feather and notice the central axis or shaft sup- 

 porting the expanded portion or vane made up of small 

 side-branches (barbs), and these in turn having smaller 

 branches (barbules). Pull two of these barbs apart, watch- 

 ing with a lens to see the part played by the barbules. 

 Are the conditions the same at the base of the vane ? Can 

 you find a downy feather among the others ? Examine it 

 carefully and see how it differs from the quills described. 

 Pick the feathers from a part of the breast and study one 

 of the pin-feathers. What parts occur in it ? 



Next pick the feathers from the whole bird. This will 

 be more easily done by dipping it in hot water. When 

 picking the feathers notice that they come from pits in the 

 skin. When the bird is picked, look for these pits. Are 

 they equally distributed on all parts of the body, or are 

 they arranged in feather-tracts ? 



In the leg see the thigh and shank (drumstick). Where 

 is the heel ? Does the bird walk on the whole foot ? Con- 

 necting the shank with the toes is the tarso-metatarsus. 

 How many toes ? Do they all point the same way ? 



INTERNAL STRUCTURE. 



Cut through the skin in the median line below from the 

 neck to the vent, being careful not to injure the deeper 

 structures in the neck. Pull the skin away. Insert a blow- 

 pipe in the mouth and inflate. This will render the 



feathers overlapping the large quills above and below are the upper 

 and lower wing-coverts. At the bend of the wing, just outside the 

 primary coverts, are short quills borne on the thumb and forming the 

 false wing (ala spuria). 



