48 CALIFORy/A ACADEMY OF SCIENCES. [Proc. 30 Ser. 



clear, but the others which were scattered through the 

 granular protoplasm, which filled the whole cavity of the 

 embryo-sac, showed no definite arrangement and did not 

 stain strongly, so that the number could not be satisfactorily 

 determined. 



VI. The Embryo. 



The changes following fertilization in Zannichellia are 

 the same as in Naias. One of the synergidee persists for a 

 short time, and the fertilized ^^g elongates before dividing. 

 The latter has a rather broader base of attachment in Zan- 

 7iichellia, so that as soon as the first division in the embryo 

 is completed, the suspensor cell already is decidedly larger 

 than the embryo cell. As in Naias, the basal cell (suspensor) 

 begins to enlarge at once, but undergoes no further division^ 



A curious variation was met with in one case shown in fig. 

 119. Here it looks as if one of the synergidae had persisted 

 and grown with the developing embryo, which was in con- 

 tact with it on one side for nearly its whole length. 



The following divisions in the embryo cell correspond 

 closely to those in Naias, but here there seems little doubt 

 that sometimes, at least, the two basal segments of the embryo 

 are formed by division of the lower of the two cells into 

 which the embryo cell first divides. It now consists of three 

 cells (exclusive of the suspensor), and the next wall is in 

 the terminal cell. This wall is nearly vertical (fig. ii4)> 

 but not infrequently is more or less decidedly oblique. The 

 exact succession of the subsequent divisions was not followed, 

 but there are formed a series of transverse walls in all the 

 primary segments, and also intersecting vertical walls in 

 the upper ones, so that the embryo shows in its upper region 

 a somewhat variable number of segments which are divided 

 into quadrants, and these are separated from the suspensor 

 by two or three undivided basal segments (fig. 116). The 

 number of transverse divisions in the young embryo is 

 greater than in Naias, and in consequence the mass of cells 



iMagnus(i87o, p.3i)refers to this enlargedbasalcell in iraaazVAf/Zia, but gives nofurther 

 particulars concerning the embryo. 



