78 



THE VITAL FUNCTIONS. 



S.^ 



examined its structure with great care, finds that each of the 

 262 ten portions into which it is divided, 

 sends out, on tlic part most remote 

 jC^ from tlic ocsopliagus (o,) two lateral 

 C-/>«?^ pouches, or caica; which, as they are 



traced along the canal, hecome both 

 wider and longer, so that the tenth pair 

 of caeca (a) extends to the hinder extre- 

 mity of the animal; tlie 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 

 animal will continue to suck blood for 

 an indefinite time: this arises from the 

 circumstance, 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. 

 i^'V'^ A structure very similar to that of 



the leech is met with in the digestive organs of the Glosso- 



264 po7^a tubercxilata, (Ilirudo com- 



planata, Linn.) of which Fig. 

 263 represents a magnified view 

 from the upper side. When 

 seen from the under side, as is 

 shown in Fig. 264,*thc cavity 

 of the stomach is distinctly 

 seen, prolonged into several 

 cells, divided by partitions, and 

 directed towards the tail. The two last of these cells (c c) 



• This figure was engraved from a drawing made, at my request, by Mr. 

 Newport, from a specimen which he dissected, and which he was so oblig-ing 

 as to sliow me. Fig. 261 represents the mouth, within wlilch 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 



