OF FERNS FROM THEIR SPORES. - 129 
cellules, shown in Suminski’s figures (pl. 2. figs. 12-16), are, like those of the antheridia, 
derived rather from the imagination than from fact. 
But the most important errors occur in the account of the development of the arche- 
gonia. The earliest stage, as seen by looking directly upon the (under) surface of the pro- 
thallium, was completely misconceived by Suminski. He overlooked the cell, forming 
part of the general surface of the prothallium and becoming the parent-cell of the papilla, 
which, from the first, lies between the embryo-sac and the external medium; so that he 
imagined the embryo-sac to be open and capable of admitting spermatozoids into its cavity. 
I examined this point most carefully, and am convinced that he was in error. Any one 
who looks at his figs. 1 and 2 of plate 3. will see that there exists no trace in them of a 
cell or cells from which the papilla (seen from above in fig. 3 of his 3rd plate) could arise, 
for the supposed orifice is bounded by seven cells, and if the papilla sprang from these it 
would consist of seven vertical series instead of four. The fact is, that his fig. 1 of pl. 3, 
stated to be from a dissection, merely shows what is seen in looking upon the under sur- 
face of the prothalliwm, without dissection ; but it represents the object focused down to 
the globule in the embryo-sac, as in my fig. 57, so that the membranes of the cells occu- 
pying the space supposed to be an orifice and forming part of the continuous surface of 
the prothallium (my fig. 56) are not seen. Fig. 3 of Suminski's 3rd plate shows a sub- 
sequent stage, where the papilla, composed of four rows of cells, is already developed; he 
has missed the gradual production of this from the cell occupying the situation of the 
imaginary orifice. i 
This clearly takes away all ground from his hypothesis of the impregnation resulting from 
the entrance of spermatozoids into the embryo-sac before the development of the papilla of 
the archegonium, and moreover proves that the bodies contained in the closed canal of this 
organ (shown in his figures, pl. 3. figs. 4-7) could not be altered spermatozoids. It will 
be remembered that I have explained these appearances in a totally different + 
With regard to the phenomena of the development of the germinal vesicle in the em- 
bryo-sac, I think it is scarcely possible to obtain such clear views of the young structures 
as Suminski has given, and I could only approximate to them by sections through the 
prothallia, while from his figures we are led to suppose that he saw them through the 
enveloping tissues, which are far too thick to allow such clear definition, especially since 
their contents soon become coagulated by the injury the preparation suffers in water and 
under pressure. All that Suminski states, therefore, respecting the development of a 
cellule at the end of the spermatozoid, inside the globular cell of the peque idm 
as the work of imagination, guided by a preconception of the necessity of some process 
‘ : : to flowe lants, namely, the 
analogous to that described by Schleiden in reference ring aa capo dii 
production of the embryo from a cellule formed in the end ofa pollen-tu , after the latter 
has become imbedded in the embryo-sac. The drawings representing the subsequent 
growth of the embryo are more or less incorrect; thus the primary, LE m 
Which remains enveloped in the tissue of the prothallium, 1s pepe ; ám ipo s 
this cellular tissue is represented as enveloping the base of the leaf and of t : in ven- 
titious root (pl. 4. fig. 10 f. of Suminski’s Essay), and the "— 700 i o napa 
direct prolongation from the base of the first leaf. The true condition is s y 
