PLANARIA FELINA. 77 



the union of the lacerated parts will prove 

 fatal. To the rest there is no clue what- 

 ever. In simple privation of the head, we 

 are more easily reconciled to conjectures 

 on the cause of it being replaced, from 

 the efforts of nature to supply a defective 

 part; but it is difficult to comprehend, why, 

 in experiments for the production of super- 

 fluous organs, it is only the anterior, and 

 never the posterior portion which protrudes, 

 that the upper division of the laceration 

 produces nothing. 



In pursuing these remarks, we may af- 

 firm, that there is perhaps a certain point 

 of the body where a head ceases to vege- 

 tate upwards, and whence a tail will vege- 

 tate down. It would be interesting to as- 

 certain where that point is placed, and whe- 

 ther it may not be connected with some 

 organic structure, which will tend to eluci- 

 date the cause of monstrosities. My own 

 experiments regarding the fact have not 

 been conclusive ; probably from being too 

 few in number, or too little diversified. A 



