244 On the Structure of the Antlieridium in Ferns. 



where tlicy suiTOund tlio j)air of c'lo.<iii,u; cells of the stomatn. 

 AVith i(\Lrar(l to the mode of their foniialion, tlicie is a still 

 iinscttkil clitierence of opinion between Iliklclirand* and 

 Strassbnrgert ; hut both of them agree in thinking that the 

 ring cells are not formed as such, but only acquire their pecu- 

 liar form subsequently. The antheridia of the rolypodiacea3 

 and KSchiztvaccai consequently present the first exam])lc of a 

 direct pn>dirciion of ring cdU hij tlic formation offannel-slidj^cd 

 septa ; they show at the same time that this ])roeess, which 

 has hitherto been quite isolated in the vegetable kingdom, 

 admits of two modifications — the ring cells being in one case 

 cut otf from a hemispherical^ and in the other from a hell-shaped 

 mother cell. It is to be hoped that I may succeed, in other 

 species better suited for the investigation than those hitherto 

 examined by me, in tracing more accurately the process of 

 septum-formation and the behaviour of the cell-nucleus during 

 that process. Only then will it be possible to decide whether 

 this new form of cell-formation ranges itself immediately 

 beside that previously observed, or whether it is essentially 

 different therefrom. 



EXPL.1XATI0X OF PLATE VI. 



Fiy. 1. Younpost observed developmental stage of a maruinal antlu'riiHuin 

 of Autinu'a hirta. The central cell possef^sc'S the form of a bi- 

 convex lens. (Drawn after treatment with caustic potash and 

 muriatic acid.) 



Fig. 2. A somcwliat older state ; the bell-shaped cell is still undivided : 

 a, fresh ; h, after the same treatment as fig. 1. 



Fig. 3. Ilalf-gi-own antlieridium; the envelope is completely formed ; in 

 the central cell the first divisions are already produced : a kb 

 as under iig. 2. 



Fig. 4. A somewhat older state than fig. 3 : a k h as under fig. 2. 



Fiq. 5. Mature antlieridium. (It was evacuated during observation.) 



Fig. 0. An antlieridium just evacuated. (To the riglit the cell-nucleus 

 of the ring cell is distinctly recognizable.) 



Fig. 7. An antheridium which has long been evacuated, seen from above. 

 Tlic inner folded wall of the ring cell is already strongly em- 

 browned ; the cell-nucleus is no longer recopnizable. 



Fig. 8. Ilalf-developtd antheridium of Codfo/itcris f//o//(Y/-o,'V''r.~\ spi-inging 

 obliquely from a marginal cell of the prothnllium. The enve- 

 lope is coni])letcly formed ; the central cell is divided crosswise 

 into four cells. (Drawn after treatment with caustic potash and 

 muriatic acid. ) 



Fig. 9. Two mature antlieridia of the same species: a, with noi-mal, uu- 

 symmetrical, b, with abuonnal, symmetrical basal cell. 



" Teber die Entn'iclielung der Famikrautspaltoflnungcn," Bot. Zcit. 

 3, p. 245. 

 *' Ein Ik'itrng zur Entv 

 Pringsheim's Jahrb. v. p. ^JOO. 



18G6, p. 24.^ 



t ''Ein Ik'itrng zur EntwickelungsgcscLichte der Spallolluungen," 



