136 N. YATSU. 



somewhere above the equator as a broad zone. The bases of 

 the ciliated lobes and the gut lie mainly in the vegetative 

 hemisphere. 



5. The cleavage (up to eight-cell stage) is normal in an egg 

 fragment obtained from the unsegmented egg, whatever be the 

 amount of cytoplasm cut off, or at whatever period. It is probable 

 that the cleavage factors do not here necessarily coincide with the 

 morphogenic ones. 



ZOOLOGICAL LABORATORY, COLUMBIA UNIVERSITY,- 

 October 29, 1903. 



