130 THE BIOLOGY OF THE ANIMAL 



d. The oesophageal or calciferous glands. — 



How many ? How arranged ? To what are they 

 connected? "What is their shape ? Size? Color? 

 Structure ? Examine under a low power a drop 

 of fluid from one of these glands. What does it 

 contain? Put one of the glands into a watch- 

 glass or test-tube containing one part of muriatic 

 acid to four parts of water. "What result ? Ex- 

 plain. 



e. The crop. — Position? Shape? "What is the nat- 



ure of its wall? "What reasons can you give for 

 this ? "What is the color of the crop ? "What is 

 the cause of this color? What does the crop- 

 contain (use microscope) ? 

 Make drawings of some of the contents found. 



/. The gizzard. — In what segments does it lie ? 

 Compare in all respects with e. 



g. The intestine. — What is its course in the body? 

 In which segment does it begin ? Structure and 

 color ? Do the septa divide it ? Note the " liver " 

 (functionally, a pancreas) on top of the intestine. 

 What is its shape ? Color? Structure? How far 

 does it extend ? Open the intestine lengthwise 

 a little to one side of the median line, wash away 

 the contents carefully with a pipette, and note 

 the folded membrane or " typhlosole " hang- 

 ing down from the roof. Does the " typhlosole" 

 extend throughout the entire intestine? What 

 is its shape ? Structure ? Compare microscopi- 

 cally the contents of the posterior end of the 

 intestine with the contents of the crop, noticing 

 especially the amount of vegetable material, such 



