BIRDS 151 



How many nostrils? In which mandible are they 

 located? Are they nearer the tip or the base of the 

 mandible? (Fig. 284.) What is their shape ? Do the nasal 

 passages go directly down through the mandible or do they 

 go backward? Is the inner nasal opening into the mouth 

 or into the throat ? 



The beak or bill consists of the upper and lower man- 

 dibles. The outside of the beak seems to be of what kind 

 of material ? Examine the decapitated head of a fowl or of 

 a dissected bird, and find 

 if there is a covering on 

 the bill which can be cut 

 or scraped off. Is the 

 mass of the bill of bony 

 or horny material ? With 

 what part of the human 

 head are the mandibles FlG - 284— skull of domestic fowl. 



/-T" o y, quadrate (" four-sided ") bone by which lower 



homologOUS ? (Fig. 284.) j aw ; s attached to skull (wanting in beasts, pres- 



Ears. — Do birds have ent in reptiles: see Fig " 277) " 

 external ears ? Is there an external opening leading to the 

 ear? In searching for it, blow or push forward the feath- 

 ers. If found, notice its location, size, shape, and what 

 surrounds the opening. There is an owl spoken of as the 

 long-eared owl. Are its ears long ? 



The leg has three divisions: the uppermost is the thigh 

 (called the "second joint" in a fowl); the middle division 

 is the shank (or "drumstick"); and the lowest, which is 

 the slender bone covered with scales, is formed by the 

 union of the ankle and the instep. (The bones of the three 

 divisions are named femur, tibiotarsus, and tarsometa- 

 tarsus.) The foot consists entirely of toes, the bones of 

 which are called phalanges. Is there a bone in each claw ? 

 (See Fig. 285.) Supply the numerals in this sentence: 



