-.-.y 



THE ANNALS 



AND 



MAGAZINE OF NATURAL HISTORY. 



[FOURTH SERIES.] 

 No. 28. APRIL 1870. 



XXIV. — On the Structure and Development of theAntheridium 

 in Ferns, By Dr. L. Kny*. 



[Plate VI.] 



The structure of the anthcridlum 'of Feni.s, notwitli.stancling 

 its great simplicity, has experienced tlie most various inter- 

 pretations. 



Niigeli, the discoverer of the organ, describes itf as a gland- 

 like structure, -wliicli is frequently apparently unicel hilar, but 

 generally presents distinctly the form of a sac surrounded by 

 a. simple cell-layer, in the interior of which the mother cells 

 of the spiral filaments are produced. It originates from one 

 mother cell. After this has projected itself above its neigh- 

 bours, it first of all divides by a horizontal septum. This first 

 septum is followed in the outer cell by a second, parallel to it. 

 The same process may be repeated once or twice in the suc- 

 cessive outer cells. )i^j these divisions a Conferva-like cel- 

 lular filament of from two to five cells is produced. Each 

 joint becomes broken up into a central cell with four peri- 

 pheral cells surrounding it. The peripheral cells of all the 

 successive joints form four perpendicular rows, and combine 

 to form a sac-like envelope ; the central " spaces " together 

 represent a " canal," in which the mother cells of the spiral 

 filaments are produced. This is closed below by the cell of 

 the prothallium to which it is attached, and above by the four 

 cells of the last joint, Avhich have not completely separated 

 from each other. The apical and basal joints sometimes re- 

 main undivided. 



When the mother cells of the spiral filaments appear to be 



• Translated by W. S. Dallas, F.L.S., from the 'Monatshfricht der 

 Kun. preuss. Akad. der Wiss. zii Berlin,' May 1809, pp. 41()-^."il. 



t Zeitsclir. fiir wissenschaftl. l^otanik, 13d. i. (lf<44) p. 10^ et fvqq-, Tuf. 4. 



Ann.<kMag.N.TItsL Ser.4. TW. v. 16 



