CELL FORMATION BY DIVISION. 



one mass before escaping ; while in Rejuvenescence the whole proto. 

 scapes without dividing. Rejuvenescence may then be regardecf 



Fi?. 33. Endosperm-cells of Phasedus multtflorus. A, the production of new cells 

 in the protoplasm of the embryo sac ; n, n, n, nuclei ; a, a, a, masses of protoplasm 

 gathered around the nuclei ; b, young cell, but without a wall of cellulose ; c, young 

 cell with a wall ; c', d. young cells with walls and vacuoles. S, two cells of the 

 endosperm in a much later stasre ; ihe cells have fused their walls so as to form a 

 false tissue ; in the angles between the cells are intercellular spaces filled with some 

 of the protoplasm of the mother-cell (embryo sac) : the cell a is in process of fission, 

 the two nuclei , n, are near together, as if formed by the fission of the original nu- 

 cleus ; s, line indicating the boundaries of the two matee* of protoplasm; the cell 

 6 is fully divided, and the two parts are separated by the wall cl. X 670.- After 

 Dippel, 



as a case of internal cell -formation in which there is no division of the 

 protoplasm. 



