On the Germination of the Spores of Ferns. 345 



" In addition to these spiral-filament organs, we find on the 

 under side of the pro-embryo near the notch of the border, on 

 the cellular protuberance lying in the middle of the frond, other 

 larger and not less important structures. These are hollow, 

 ovate bodies, and consist of a papilla formed of ten to twelve 

 cells, while the other organs seldom exhibit more than one. 

 Their number is indefinite, since there are often only three upon 

 one pro-embryo, while upon another of the same species appear 

 eight or more. They differ from the above-mentioned organs 

 not only in these points, but in their mode of origin and their 

 structure. It is clear from the course of development that they 

 are not spiral-filament organs in a more perfect condition. In 

 the origin of these organs the cellular layer becomes thickened 

 by the formation of new cells ; in the course of this process a 

 large globular intercellular space is formed having a contracted 

 orifice at the outer end. This latter is usually hexangular, and 

 is immediately surrounded by green, usually quadrangular cells. 

 The cells further from it are larger and contain less chlorophyll. 

 From the borders of this cup-like orifice arise four largish cells, 

 containing merely a clear fluid, often with nuclei, and arranged 

 in a circle; these leave a square intercellular space between 

 them varying in size. From each of these cells three more are, 

 as a rule, developed vertically one above another, so that the 

 square space becomes elongated into a canal leading to the inte- 

 rior of the organ. The cells at the apex are usually applied 

 together so as to close the orifice. The early origin of the canal 

 causes the still uncovered cavity to be rarely met with. 



" These structures, so different in anatomical character, which 

 were formerly regarded as antheridia in a different stage of de- 

 velopment, also assume a distinct physiological import. 



" By continued observation I have succeeded in discovering in 

 them the sexual apparatus of the Ferns, hitherto regarded as 

 Cryptogamic. In the above-described hollow, ovate organs oc- 

 curring on the middle of the pro-embryo, I have recognized the 

 female apparatus; a circumstance, the establishment of which 

 claims for the spiral-filament organs the import of male appa- 

 ratus. The former, which is an ovule without envelopes, there- 

 fore a simple naked nucleus, is to be divided into two parts ; one, 

 the larger and upper portion projecting from the pro-embryo, 

 the nuclear papilla (mammilla nuclei), and the other smaller, buried 

 in the pro-embryo, the cavity for the embryo-sac (antrum nuclei). 

 In the former we have again to distinguish : the orifice at the 

 apex, the foramen of the nuclear papilla (ossiculum mammilla 

 nuclei) ; and the prolongation of it leading into the cavity for the 

 embryo- sac, the canal of the nuclear papilla (canalis mammilla' 



