NUTRITION IN THE ANNELIDA. 



103 



finds that each of the ten portions into which it 

 is divided sends out, on the part most remote 

 from the oesophagus (o), two hiteral pouches, or 

 caeca ; which, as they are traced along the 

 canal, become both wider and 

 longer, so that the tenth pair 

 of cffica (a) extends to the 

 hinder extremity of the animal; 

 the intestine (i), which is very 

 short, lying between them.* 

 It has long been known, 

 that if, after the leech has 

 fastened on the skin, a portion 

 of the tail be cut off, the ani- 

 mal will continue to suck 

 blood for an indefinite time : 

 this arises from the circum- 

 stance that the caecal portions 

 of the stomach are laid open, 

 so that the blood received into 

 that cavity flows out as fast 

 as it is swallowed. 

 A structure very similar to that of the leech is 



* This figure was engraved from a drawing made, at my re- 

 quest, by Mr. Newport, from a specimen which he dissected, 

 and which he was so obliging as to show me. Fig. 261 repre- 

 sents the mouth, within which are seen the three teeth ; and 

 Fig. 262, one of the teeth detached. A paper, descriptive of 

 the structure of the stomach of the leech, by Mr. Newport, was ' 

 lately read at a meeting of the Royal Society. See the abstracts 

 of the proceedings of the Society, for June, 1833. 



