Il6 THE ENGLISH SPARROW. 



covering of the tarsus. What group of animals has a similar 

 covering over the whole body ? By reason of its scales the front 

 part of the tarsus is said to be scutellate. The hind part is 

 netted or reticulate. 



c) The toes are four in number. Compare with a cat in this respect. 



They are termed, respectively, the hind toe, the inner toe, the 

 middle toe, and the outer toe. The first mentioned opposes the 

 other three in grasping. Note the effect on the toes of placing the 

 leg in a squatting or perching position. How is a bird able to 

 cling to a perch when asleep ? Each toe terminates in a claw 

 and has a covering similar to the tarsus. What part of the leg is 

 feathered ? Do birds differ in this respect ? 



d) The fore limbs or wings will be found to have the same number of 



divisions as the legs, the corresponding parts being an upper-arm, 

 a fore-arm, and a hand. Feel for the thumb at the base of the 

 hand in front. Two fingers are distinguishable on the plucked 

 bird, one forming the tip of the wing and the other projecting from 

 the hind border of the hand about one third way back from the tip. 

 Look for these fingers later, after you have stripped the feathers 

 from your bird. Also notice then the alar membrane stretched 

 between the upper-arm and fore-arm on the anterior border. 



e) The beak consists of an upper and a lower mandible, each covered 



with a horny sheath. Are teeth present ? Near the base of the 

 upper mandible are the nostrils. Probe them with the head of a 

 pin and discover where they open into the mouth. With the 

 forceps seize the tip of the tongue and pull it about, noting its 

 attachment and shape. 



f) Note the position and color of the eyes. Raise the upper eyelid 



and look in the inner angle of the eye for the nictitating mem- 

 brane. Draw the latter down over the eye with the forceps. 

 What is the function of this membrane ? 



g) Push the feathers aside and look for the ear-opening back of the 



eye. Is there any external fold or structure for catching the sound ? 



h) Feel about the base of the tail feathers for a short conical projection 



of the trunk the uropygium. This is the true tail of the bird, 



