56 PLANARIA FEL1NA. 



This kind of regeneration seems univer- 

 sally diffused among the species ; most of 

 those, removed from their native abode, un- 

 equivocally shew the acquisition of the pos- 

 terior extremity. But these facts merit 

 more explicit detail 



On the tenth of November 1810, a small 

 fragment was detached from the tail of each 

 of two planariae. Next day, as sometimes 

 happens, they had removed from the spot 

 of separation, to await in quiescence the ex- 

 ercise of their reproductive powers : which 

 were not slow of being unfolded. On the 

 twenty-second of the month, both had ac- 

 quired complete heads, and were vigorous- 

 ly traversing every part of their element ; 

 though still very small, being hardly one- 

 fifth of the size of the original animals. 

 The regeneration of each defective trunk 

 was likewise now so fully accomplished, 

 that it could with difficulty be known 

 which of the planariae, compared with 

 others, had lost the fragments. The new 

 animals had at that time resumed their 



