106 PLANARIA ARETHUSA. 



wbole planaria. In six days, its motion was 

 manifest, and on the eighteenth of the month, 

 a white papilla was vegetating from the sum- 

 mit. The organic reproduction appeared 

 complete on the twenty-second ; the new 

 animal traversed the surrounding element, 

 though its figure neither was so well defi- 

 ned, nor were its motions so lively as dis- 

 played by two regenerating fragments of 

 the planaria felina which had separated la- 

 ter. On the twelfth of November, it had 

 nearly acquired the shape of a full grown 

 planaria ; and the two specks or eyes were 

 conspicuous with the microscope on the 

 twenty-third. Perhaps they might have 

 been found earlier, had ray attention been 

 so directed. 



The fragments thus separating and be- 

 coming perfect animals, never attained the 

 dimensions of the parent whole. While in 

 possession of the observer, they always re- 

 main infinitely smaller. It should also be 

 remarked, that no feeding will preserve the 

 size of any planariae when removed from 



