ZOOLOGY AND BOTANY. MICROSCOPY, ETC. 255 



has been stated by previous observers. The very thin endospore exhibits 

 the reactions of cellulose, the three layers of the exospore those of 

 cuticularized membrane ; the very thin nearly transparent epispore is 

 apparently derived from the epiplasm, not from the protoplasm of the 

 mother-cell. The first wall in the germinating microspore is at right- 

 angles to the shorter axis of the spore, and divides it into a small basal 

 cell, which again frequently divides into two cells of very unequal size 

 which represent the vegetative part of the prothallium, and a much 

 larger upper cell, the mother-cell of the antherid. The further divisions 

 in the latter closely resemble those in Polypodiacese ; the normal number 

 of antherozoids is thirty-two, formed by repeated divisions in the central 

 cell of the antherid, not by free-cell-formation. The vegetative part of 

 the prothallium is separated from the mother-cells of the antherozoids 

 by a strong wall, the basal cell of the antherid intervening between 

 them. Eventually the wall of the microspore is ruptured by the ab- 

 sorption of water by the internal walls ; owing to its strong turgescence 

 the cap-cell is very conspicuous just before the rupture. The gradual 

 development was followed out of the nuclei of the mother-cells into the 

 antherozoids, which are furnished v/ith a large number of cilia, as in 

 other Vascular Cryptogams. The attached vesicle is large, and is sur- 

 rounded by a very delicate membrane; occasionally the swarming 

 antherozoid frees itself entirely from the vesicle. 



The structure of the megaspore and the succession of its early 

 divisions are much as has been described by previous observers. The 

 mother-cell of the archegone is distinguished from the other cells by its 

 central position and by its more densely granular protoplasm. The 

 ventral canal-cell appears to be formed not by further division of the 

 central cell, but by division of the primary canal-cell. Fecundation 

 takes place very soon after the archegone opens, and the oosphere 

 becomes almost at once surrounded by a membrane which prevents the 

 further penetration of antherozoids; as soon as the latter enters the 

 oosphere it appears to undergo similar changes, only in reverse order, 

 as those which it underwent in transforming itself from a nucleus of a 

 mother-cell to an antherozoid. 



The first divisions of the embryo are into two primary cells, and 

 then into four quadrant-cells, which Dr. Campbell regards as of equal 

 morphological importance. The development is described in detail, 

 from the four quadrants respectively, of the first leaf, the first root, the 

 stem, and the foot. In the leaf the apical growth ceases early ; the 

 apical cell of the root is from the first very conspicuous, and immediately 

 recognizable as such. The apical cell of the stem is formed indifferently 

 from either of the two octants of the stem-quadrant. The first leaves 

 show scarcely' a trace of the circinate vernation of the later ones. 



From the very great resemblance in the structure of the antherid, 

 the author derives a conclusion favourable to the very close relationship 

 of the Marsileacese to true ferns. 



"Bulblets" of Lycopodium lucidulum.*— Mr. E. E. Sterns de- 

 scribes the bulblets of Lycopodium lucidulum Michx., which are borne on 

 the end of the 6-bracted stipes. These stipes are short thickish sub- 

 terete ascending branches, not axillary in any sense, but occupying, 

 side by side, the exact position of leaves. The bulblet resembles the 



* Bull. Torrey Bot. Club, xv. (1888) pp. 317-9, and xvi. (1889) pp. 21-2 (3 tigs.). 



