PLANARIA FELINA. 81 



probably soon have witnessed the further 

 advance of that organ to perfection. 



It is thence to be concluded, that where- 

 ever a strong tendency to action is display- 

 ed by a shapeless reproduction or vegeta- 

 tion from an entire planaria, an organ, the 

 most important to all animals, the head, 

 will finally be developed. 



Doubts frequently occurred, whether a 

 duplication of the tail would invariably be 

 produced by an incision towards its extre- 

 mity. Notwithstanding such seems to be 

 the general law of nature, anomalies here 

 bewilder the observer. In one planaria, 

 the portion generated was much longer 

 than the original tail ; it was endowed with 

 more activity than is peculiar to that organ, 

 and, as in the former instance, its motions 

 had greater similarity to those of a head. 

 No marginal specks appeared. Another 

 experiment of this kind was made on the 

 twenty-seventh of November 1811. A new 

 extremity accordingly protruded ; but about 

 the eleventh of February 1812, the origi- 



