AND THE LOWEE ANIMALS. G3 



The alimentary canal begins as a very short and wide 

 oesophagus, and ends in an intestine, somewhat of the 

 same kind, but which can hardly be said to consist of 

 two regions. Between these organs we find a stomach 

 disproportionately large, which fills almost the entire 

 cavity of the body. In addition to these, two salivary 

 glands, composed of long tortuous tubes, are attached 

 to them in front, and six well-formed biliary canals, 

 which represent the liver, are connected with them 

 behind. Opening into the mouth and the spinning 

 apparatus which we alluded to before, may be seen 

 two peculiar organs, which extend in a tortuous man- 

 ner along the entire length of the stomach, and whose 

 office is the secretion of the fluid from which the silk 

 is formed. Every portion of this digestive apparatus 

 is calculated to extract the nutritious materials from 

 the crude masses of unsubstantial food which has been 

 imperfectly prepared by the action of the jaws. 



Even on the second day after the caterpillar has 

 been converted into the chrysalis, very considerable 

 alterations may be observed. The oesophagus is 

 narrowed and elongated ; the intestine, similarly modi- 

 fied, is now divided into two well-marked regions; 

 the stomach has been diminished by about one-half 

 of its breadth and a quarter of its length ; the salivary 

 and biliary glands have been shortened, and the 

 organs which secrete the silk have become smaller. 

 On the eighth day, the entire digestive tube is exactly 

 like a spindle one half of which is covered with thread, 

 and which is loaded with lead in order to balance it. 

 The oesophagus represents the upper portion of the 

 spindle ; the stomach corresponds to the middle, which 

 is covered with thread ; the small intestine to the thin 



