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THE AMERICAN NATURALIST [Vol. XLII 



observations just mentioned were to the effect that both 

 male nuclei were present in the sac after the endosperm 

 nucleus had proceeded to divide. At any rate, whether 

 the endosperm nucleus requires fertilization or not, it 

 precedes the egg nucleus in division. This fact supports 

 the theory that the endosperm is a portion of the gameto- 

 phyte. 



The first division of the egg cell is periclinal, forming 

 two cells, the distal one of which is destined to give 

 rise to the embryo and the other the suspensor. These 

 two cells then divide almost simultaneously, the former 

 transversely, lengthening the suspensor, the latter longi- 

 tudinally. Either may, however, precede the other in 

 dividing. The four-celled stage is formed by a division 

 of the two cells in a longitudinal plane at right angles to 

 the first plane. One or both, generally one, of the cells 

 of the suspensor divides transversely, thus completing 

 the suspensor which possesses three or four cells (PI. II, 

 Fig. 20). The proximal cell often broadens at its base. 

 The next division of the embryo cells is at right angles 

 to the other two planes of division and results in an eight- 

 celled stage (Fig. 20). About this time the distal cell of 

 the suspensor makes two longitudinal divisions at right 

 angles to each other (PI. II, Figs. 21-22). Numerous 

 divisions follow in the usual manner (Figs. 21-22). In 

 the last stages the exact arrangement of cells was hard 

 to determine on account of the difficulty in sectioning the 

 hardened wall of the sac. But the shape of the mature 

 embryo with its two cotyledons and the approximate 

 arrangement of cells' are shown in Fig. 23. The embryo 

 lies in a cavity about twice its size and so does not come 

 into contact with the endosperm except at the base of the 

 suspensor. 



The development of the endosperm is essentially sim- 

 ilar to that of Ranunculus. The endosperm nucleus, 

 fertilized or not, divides successively to form several 

 nuclei distributed throughout the cytoplasm which radi- 

 ates from them as centers. The antipodal cells number- 



