Il8 THE ENGLISH SPARROW. 



Exercise 2. Draw one of the legs on a scale o] two. 



A FEATHER. Pluck one of the large primaries from a wing and note 

 the following parts: 



a) The central shaft composed of a hollow basal quill and the longer, 



angular rachis extending to the tip of the feather. 



b) The expanded portion called the vane. Why is the rachis not in the 



center of the vane ? Can you find any wing or tail quills that 

 differ in this respect from the primary you are studying ? 



c) The vane, under the lens, is seen to be composed of side branches 



from the rachis barbs and these, in turn, to have lateral 

 barbules. The barbs and barbules are locked together by tiny 

 hooks, thus presenting one unbroken surface in resisting the air 

 during flight. 



d) At the tip of the quill note a tiny opening, the inferior umbilicus, 



into which a papilla of the skin once fitted. At the junction of the 

 quill with the vane, on the under side, is another opening, the 

 superior umbilicus. 



e) Compare the primary just studied with a down-feather, a pin- 



feather, and one of the hair-like filoplumes about the mouth. 



Exercise 3. Draw one of the large primaries on a scale of two, showing 

 the under side. 



Exercise 4. Pluck the bird and draw a lateral view of the entire specimen, 

 naming all the parts. 



Exercise 5. Draw an enlarged side -view of the head. 



INTERNAL ANATOMY. On account of its larger size a pigeon would 

 be better for a study of the internal organs than a sparrow, but by 

 exercising a little more care the latter will serve the purpose very well. 



Technical Note. After plucking the bird lay it on its back and fasten it to 

 a small board by pins or tacks through the feet and outstretched wings. 

 With a pair of fine pointed scissors slit the skin along the mid-ven- 

 tral line from the cloacal opening to the base of the lower mandible. 

 Work the skin back from the sides of the body and pin it out. 



