8 MR. HENFREY ON THE DEVELOPMENT 



varied ; sometimes it half enveloped the tegmen, in some ovules it had grown up further 

 over it. The inner coat, the tegmen, had not grown over the nucleus in all the ovules, 

 but in most it projected beyond. The nucleus was still covered by its own cellular coat, 

 and still contained only the clear, colourless fluid with black points. 



May 16th. The ovaries more advanced ; the pistillary cords extended nearly to the base 

 of the ovary, lying in the grooves formed between the projecting placentas and the walls 

 of the ovary, apparently free, and composed of delicate tubes presenting all the characters 

 of pollen-tubes, and apparently continuous with these, as derived from the pollen on the 

 stigma. The ovules (fig. 8) exhibited considerable alteration. Most of them were en- 

 larged, and the outer coat had developed much in the chalazal region ; its cells were larger 

 and more clearly defined. The inner coat, which appeared to be tolerably independent of 

 the outer at the sides, as air passed freely between them, had grown up far beyond the 

 nucleus, and its cell-walls had acquired more consistence. The nucleus was much 

 changed ; the embryo-sac had lost its proper cellular coat, which had disappeared either 

 by solution or by pressure, probably the former, as a free space existed sometimes be- 

 tween the inner coat and the nucleus ; and in some cases the solution appeared imperfect, 

 extending only to the cross walls of the cells, so that the embryo-sac was contained in an 

 outer sac consisting merely of the outer walls of the cells of its coat. The embryo-sac 

 now had the aspect of a large ovoid sac attached by a cellular pedicle to the chalazal 

 region, and contained opalescent mucilaginous matter (protoplasm), in most cases accu- 

 mulated at the ends, chiefly at that next to the micropyle. There was no sign of a nu- 

 cleus or nascent cell yet. 



May 20th. The embryo-sacs exhibited the collections of protoplasm at the two ends. At 

 the micropyle end new phenomena presented themselves : either one, two, or (and 

 usually *) three minute vesicles (figs. 11-14) had been formed from the protoplasm, and 

 always seemed to me to originate as cavities excavated in the mucilage, not as if formed by 

 the formation of membrane on the outer surface of a nucleus (cytoblast) or globule of 

 mucilage. These vesicles soon appeared as distinct cells, with exceedingly delicate walls, 

 lying at the micropyle end of the embryo-sac, and undoubtedly existed there before the 

 pollen-tubes entered the foramina of the ovules. 



In some of the ovules examined this day the pollen-tubes had entered the ovules, and I 

 traced them down through the wide mouth of the outer coat and the narrow canal of the 

 inner, as far as the apex of the embryo-sac. They never entered this, but generally 

 appeared to be diverted a little to one side, and to he in contact with its outer surface t, 

 just over the place where the minute vesicles lie within. 



May 31st. I examined a number of ovules in various stages, repeating the observations 

 on the earlier conditions with similar results. I traced the pollen-tube down to the em- 

 bryo-sac in several specimens (fig. 15) : in one case it appeared flattened against the mem- 

 brane of the embryo-sac (fig. 17) ; in other cases (figs. 15, 16, 19, 20) I traced it a little way 



* It is probable that there are always three ; but as they vary in size and lie close together, one or even two of them 

 may be hidden in certain cases. 



t The end of the pollen-tube exhibits dark contents when in contact with the embryo-sac. 



