280 Linnean Society. 
published ; Mohl, who gives the most complete account of the deve- 
lopment in Orchis Morio, having given no drawings. In the first 
stage, examined on the 3rd of May, the ovules of flowers which were 
just opened and were without signs of pollen on the stigmatic sur- 
face, were just curving over towards the anatropous position ; the 
nucleus projected beyond the cells forming the single coat of the 
ovule, and consisted of a large central cell (the embryo-sac) enclosed 
by a layer of very delicate cells of small size, constituting a proper 
coat of the nucleus. On the 9th, the ovules of fully-expanded 
flowers were not much altered except in the much clearer definition 
of the walls of the cells. The embryo-sac was filled with a clear 
colourless fluid, in which floated minute black atoms. In some 
flowers the stigma was smeared with pollen, which sent down nume- 
rous tubes, about ;,4,,th of an inch in diameter and at most one- 
fourth of the size of the smallest surrounding cells. On the 138th, 
when the flowers were withered and the stigmas were covered with 
pollen, a dense bundle of tubes lay in the midst of the lax tissue of 
the canal leading to the cavity of the ovary. Some of the ovules 
were completely anatropous, while others were about three-fourths 
curved, the former being about ;1,th of an inch in length. The 
two coats of the ovule were now distinctly evident, and the nucleus 
was still covered by its own cellular coat, and still contained only 
the clear colourless fluid with black points. On the 16th, the pistil- 
lary cords extended nearly to the base of the ovary, presenting all 
the characters of pollen-tubes, and apparently continuous with those 
derived from the pollen on the stigma. Both coats of the ovules 
had become considerably developed, and the inner had grown up far 
beyond the nucleus; the embryo-sac had lost its proper cellular coat, 
had acquired the aspect of a large ovoid sac attached by a pedicle to 
the chalazal region, and contained opalescent mucilaginous matter 
(protoplasm), in most cases accumulated at the ends, chiefly at that 
next the micropyle. On the 20th, the last-mentioned appearance 
continued ; and at the micropyle end, one, two or (usually) three 
minute vesicles had been formed, always seeming to originate as 
cavities in the mucilage, and not as if derived from the formation of 
a membrane on the outer surface of a nucleus or cytoblast. These 
vesicles soon took the appearance of distinct cells with exceedingly 
delicate walls, and undoubtedly existed before the pollen-tubes en- 
tered the foramina of the ovules. In those ovules which had been 
penetrated by the pollen-tubes, these were traced by Mr. Henirey 
through the wide mouth of the outer coat and the narrow canal of 
the inner, as far as the apex of the embryo-sac, which however they 
never entered, but generally appeared to be directed a little to one 
side and to lie in contact with its outer surface, just over the place 
where the minute vesicles lie within. On the 31st, the previous 
observations were repeated and confirmed on specimens in various 
stages of growth. At this period, in some of the embryo-sacs one 
of the vesicles had become divided into two cells by a horizontal 
septum, the upper cell dividing again and growing out through the 
endosteme in a conical form to produce the confervoid filament de- 
