204 



LEMON. 



found in two worms which had been split near the middle line 

 of the body. One was split through the head back to the 

 pharynx but not including it. After several operations two 

 heads developed, and it was noticed that the pharynx was grad- 

 ually increasing in width. This continued until the two heads 

 were fully formed, when it had reached a size nearly twice that 

 of the normal. 



The other case was a worm whose tail had been split to the 

 base of the pharynx. After the operation the pharynx in- 

 creased continually in width until two tails were fully formed. 



LABORATORY OF EXPERIMENTAL MORPHOLOGY, 



MICHIGAN UNIVERSITY, 

 ANN ARBOR, MICH., July 28, 1899. 



