THE SUNFISH AND THE SPARROW 15 



and, examining the vanes with the lens, find out what has 

 happened; now rub from base to tip, and note, under a 

 lens, the result. 



Examine a plucked-out contour feather. HOW T does it 

 differ from the quill feather? Can you understand its 

 structure from your study of the quill feather? Note that 

 the tip of the feather is colored and marked while the base 

 is not especially patterned. Why is this ? Examine a down 

 feather. How does it differ in make-up from a quill feather? 

 From a contour feather? What is the special use of the 

 down feathers? Finally, pluck out one of the hair-like 

 thread feathers from the base of the bill and examine it with 

 the lens to determine its structure. 



Make a careful drawing of each of the four kinds of 

 feathers, naming all the parts. 



In classifying birds reference is made in the manuals of 

 classification to differences in the shape and character 

 of many parts of the body and to differences in the plumage 

 of various body-regions. To understand these references it 

 is necessary to become acquainted with the names applied 

 to these various small parts and regions, and so in fig. 7 

 the names of them are given. 



Examine the bill or beak. It is composed of an upper 

 and a lower mandible or jaw; the meeting line of the man- 

 dibles is called the commissure, and the corner of the 

 mouth is called the rictus; the bristles at the rictus are the 

 rictal bristles; the median ridge of the upper mandible is 

 the culmen, and the median keel of the lower mandible 

 the gonys. Note just above the bill two openings. What 

 are they ? How are they connected with the mouth ? Note 

 the eyes, and at the inner angle of each the delicate nictitat- 

 ing membrane, which can be drawn over the ball. Does 

 the bird have external ears? The names of the regions of 

 the head which are commonly referred to in describing its 

 markings will be learned from fig. 7. 



