OF FERNS FROM THEIR SPORES. 131 



Lastly, it is unnecessary to criticise Dr. Wigand's views as to the origin of the embryo, 

 or, as he calls it, the " bud " of the new plant, since he admits that he did not trace 

 the earlier stages of its development, and seems never to have investigated it by sec- 

 tions, so as to see the relations with the embryo-sac. His opinion was that no relations 

 did exist. 



Shortly after the appearance of Dr. Wigand's memoir, M. G. Thuret * published an 

 account of the antheridia and their contents, the particulars of which agree pretty closely 

 with those I have given. He states the structure of the antheridiwm to be less simple than 

 Suminski and Wigand had described it, consisting of a parent-cell of the sperm-cells sur- 

 rounded by an annular cell, but not by a collection of flattened cells such as Schacht and 

 Hofmeister describe. He does not enter minutely into the development of the spermato- 

 zoids, but describes them accurately, excepting, as I believe, in reference to the hyaline 

 vesicle, which he says they ordinarily drag about with them ; this vesicle, which in a later 

 paper f he states to be in all probability a product of the spermatozoid, I consider to be 

 the parent sperm-cell, from which the spermatozoid has not completely extricated itself, 

 and I did not find it in the majority of cases. 



In the same year M. Hofmeister published a brief preliminary summary of his obser- 

 vations on the reproduction of the Cryptogamiaf , wherein he arrived at conclusions which 

 approximate pretty closely to those I have given, but to which I shall refer more par- 

 ticularly presently, in analysing the portion referring to the Ferns of his great work on 

 this subject. 



The next important contribution was an elaborate paper by M. Schacht §. In exami- 

 ning this it is unnecessary to repeat the particulars in which he agrees with all other 

 authors, and I shall therefore confine myself to the debated points. 



In reference to the antheridia, where he differs from Thuret and myself, he states that 

 le envelope of the parent-cell of the sperm-cells is composed of a number of cells, the 

 annular cell which I have described being supposed to be divided by four perpendicular 

 rails, so as to form four cells constituting a quadrangular boundary to the central cell. 



lere a horizontal septum exists, the envelope would consist of eight cells forming two 

 circles of four. This view I hold to be incorrect, for I never could see the numerous boun- 

 dary lines which such a structure would exhibit, in the hundreds of antheridia which I 

 have examined. He also supposes that the sperm-cells originate by free cell-formation in 

 the central cell, which I must distinctly deny. 



Schacht describes the spermatozoids as having four and a half or five turns in the 

 spiral coil ; I believe three to four is the utmost : moreover, he regards the widest con- 

 volution as the anterior, a view which I cannot explain, and he states that this passes into 

 a vesicular structure which swells up in water (as described by Thuret) ; this I consider 

 the sperm-cell, still adherent to the spermatozoid. 



* Note sur les Anthe'ridies des Fougeres, par G. Thuret, Ann. des Sc. Nat., 3rd Ser., Botanique, t. xi. p. 5. 

 f Ann. des Sc. Nat., 3rd Ser., Botanique, t. xvi. p. 29, 1851. 



X Ueber die Fruchtbildung und Keimung der hoheren Kryptogamen. Botanische Zeitung, vol. vii. p. 793, 1849. 

 § Beitrage zur Entwickelungsgeschichte der Farrenkriiuter, von Hermann Schacht. SchlechtendahPs Linnsea, xxii. 

 p. 753, 1849. 



