OF FERNS FROM THEIR SPORES. 133 
In the same year appeared an essay on this subject by Dr. Von Mercklin*, which I 
have not seen, but I am able to state the principal points in it, from the circumstance of 
his having published an abstract of them in the ‘ Linnæa t, in answer to Schacht's criti- 
cism of Suminski’s views. 
Von Mercklin states that the antheridia appeared to him to consist of never more than 
five cells; sometimes they appeared still more simple, but he gives no details in his 
abstract. Of the spermatozoids he says that the figures given by Thuret and Wigand 
agree best with his observations, those of Suminski worst, but he regards the large vesicle 
figured by Schacht at the extremity of the widest coil, as the adherent sperm-cell. He 
also considers the broad convolution to be the posterior, since the spermatozoid always 
advances with the narrow end foremost; in this his statements accord with my own 
observations. 
In reference to the archegonia, he truly says that Schacht overlooked the earliest stages, 
and he asserts that although he is not positive concerning all cases, he has distinctly 
seen an orifice into the cavity of the archegonium (the intercellular cavity, as he and 
Schacht consider it, but the embryo-sac of my description) in the situation of the cell from 
which the papilla grows up, pretty much therefore what Suminski described. Moreover, 
he states that he has seen spermatozoids enter this. But he does not appear to attribute 
importance to any particular: epoch for the contact of the spermatozoid with the embryonal 
vesicle, which lies in the cavity (embryo-sac), for he states that of the three times he 
witnessed this phenomenon, in the course of an entire year’s observation of the subject, 
the spermatozoids twice entered the nascent organ, as described by Suminski, and in the 
. other case entered the open canal of a fully developed archegonium, to reach the “ germ- 
cell” (embryonal vesicle). He states his belief that the mucilaginous filaments seen by 
Schacht, Mettenius, &c., in the canal, are really altered spermatozoids, and he concludes 
with the following assumptions :— 
* 1. The spermatozoids do regularly enter into the archegonia; and, 2. Probably con- 
tribute to the origin or the development of the first.*germ-frond. How this takes place 
I know not, and the details concerning it, given by Count Suminski, remain for the pre- 
sent unconfirmed.” and 
The last observations to which I have to refer are those contained in M. W. Hofmeister's 
recent work tf, forming part of an elaborate series of investigations on the reproduction of 
the higher Cryptogamous plants. : 
This adie a describes the antheridium as a more complex structure than I 
and Thuret imagine it to be, since he believes the walls enveloping the central parent-cell 
of the sperm-cells to consist of four or eight cells, constituting a quadrangular boundary, 
instead of being simply one or two annular cells. He further states that he found, on sung 
prothallia produced by budding from old barren and proliferous prothallia, antheridia of the 
* Beobachtungen an dem Prothallium der Farrenkräuter, von Dr. C. E. von Mercklin. St. Petersburgh, Xd 
T Zu den Untersuchungen über die Entwickelungsgeschichte der Farrenkräuter, von Dr. C. E. von Mercklin. 
Schlechtendal’s Linnæa, xxiii 723. 1850. 
_ . t Vergleichende Untersuchungen der Keimung, Entfaltung und Fruchtbildung höherer Kryptogamen, &c. 4to. 
Leipzig, 1851. 
VOL. XXI. T 
