84 STUDIES OF ANIMAL TYPES 



but smaller bodies. These are the barbules. The barbules 

 interlock by means of very small hooks, thus forming a con-* 

 tinuous sheet. The feathers that overlie the body and form 

 the contour of the body are called the contour feathers. 

 Pull off the contour feathers on a small space and note the 

 down feathers. There are also other hairlike feathers that 

 may be exposed, called filoplumules. They are seen on a 

 chicken before it is singed. Separate the feathers above 

 the base of the tail and find the oil gland. 



Observe that the feathers extend down the leg over the 

 knee, leaving only the ankle exposed. How many toes has 

 a sparrow ? It is a perching bird, so note the arrangement 

 of the toes. 



B. INTERNAL FEATURES. Lay the bird on its back on 

 a pine board, stretch the wings and legs out, and tack them 

 to the board. Part the feathers and, with a pair of scissors, 

 cut just through the skin along the middle line from the 

 tail to the base of the lower mandible. Work the cut edges 

 of the skin loose from the sides of the body, and pin out of 

 the way. Note the edge of the breastbone, or sternum, 

 in the middle line. Note on each side the large pectoral 

 muscles that move the wings. It is these muscles that 

 furnish the white meat, or breast, of a turkey or chicken. 

 Where are the largest muscles in a frog ? Why ? 



Cut away all the breast muscles. Note the lateral ribs 

 attached to the sternum. Note the wishbone in front of the 

 sternum. It is made up of the two collar bones, clavicles, 

 grown together at their inner ends. Note the coracoid 

 bones extending from the anterior end of the sternum. 

 Remove the wishbone and coracoid bones, cut away the 

 abdominal wall, and. cut the ribs from the sternum on each 

 side and remove the sternum entirely. At the base of the 



