DISSECTING OBJECTS. 



125 



may be cut from the body with a scalpel or pair of scissors, and 

 be mounted in fluid or in balsam. 



2. The Digestive System consists of the pharynx; the oeso- 

 phagus, or gullet ; the craw, or crop ; the gizzard, or ventri- 

 culus , the stomach, or duodenum ; the intestines ; and a 

 number of slender membranous tubes, filled with a fluid 

 analogous to bile. In addition to these, the salivary glands 

 may be mentioned.- '. .. 



There is a very great variety in the digestive apparatus of 

 insects. In those which feed on flesh, the alimentary canal is 

 short, as in the higher animals, and in the vegetable eaters it 



Fig. 36. 



is long. There are also differences of structure which clearly 

 show the adaptation of means to ends. A, Fig. 36, is the 



11* 



