100 PLANARIA ARETHUSA. 



which it cannot be desirable to repeat, the 

 ahment continues to be absorbed for a very 

 considerable time, and is discharged from 

 the mutilated end. Regular contractions 

 and dilations are all the time performed as 

 if the proboscis were untouched. On dis- 

 section, the upper part seems to communi- 

 cate with other vessels, traversing the body 

 or branching to each side ; but the gelati- 

 nous consistence of the animal, and its in- 

 variable contraction when dead, unite in 

 opposing the researches of the physiologist. 

 Probably this is the only part of a planaria 

 which is not reproduced into a new animal, 

 though it be regenerated where defective. 

 The proboscis of the whole individuals 

 which I have examined, is of a milk-white 

 colour from the root to the mouth. It is 

 entertaining to observe the operation of its 

 functions. The power of the planaria over 

 it seems almost unlimited, and by its sin- 

 gular flexibility, it can be extended, bent, 

 and contorted in every possible direction. 

 Sometimes it is protruded from the tail t A 



