136 MR. HENFREY ON THE DEVELOPMENT 
It would be out of place to enter into a detailed examination of these discoveries at the 
close of this long memoir. They are to be found in the work of Hofmeister * already 
quoted in regard to the Ferns. I may also refer to a resumé of the present state of know- 
ledge on these subjects, published by myself in the ‘ Annals of Natural History +,’ for the 
facts and general conclusions to be derived from them, and to a Report furnished to the 
British Association in 1851, for an account of the historical development of these questions 
during late years. 
I cannot conclude without once more directing attention to the many striking analogies 
recently revealed between the phenomena of reproduction in plants and in animals. They 
must excite the strongest interest in the minds of all those pursuing the study of biolo- 
gical laws. Many of the facts rest, at present, it is true, upon the authority of but one or 
two observers, and it can scarcely be doubted that much remains to be discovered before 
all the details are sufficiently established. The investigation of the reproduction of Ferns 
is the point which has been most pursued hitherto, and even here there is considerable 
discrepancy in reference to anatomical conditions. My own observations have satisfied 
me only after prolonged and careful study of the subject; for where we have to compare 
successive stages in distinct preparations, and this by means of dissection of microscopic 
structure, there are very numerous inlets for misconceptions. If I have fallen into errors, 
I trust they may be soon detected by other observers, whom this memoir may attract to 
similar researches. 
London, May 1852. 
DESCRIPTION OF THE PLATES. 
TER XIV. 
[The specimens were in most cases self-sown 
rn: plants, and moreover were often mingled before exami- 
3 
pus a that sat unable to say more than that they belonged principally to an unknown Adiantum, 
n Asplemum, I'teris serrulata, and Gymnogramma chrysophylla. Most of the stages, however, were 
rain repeatedly in the last species. The drawings were all made in outline with the aid of the camera, 
ucida eye-piece, except in the cases of Figs. 33, 41-47, and. 75.) 
Figs. 1 & 2. Germinating spores: the se i i 
ee ie ee cond figure m a radical filament. 
Figs. 5-8. Subsequent stages, in which lateral expansion is going on 
Fig. 9. A young prothallium, in which the peculiar obcordate form W alread 
Fig. 10. Under surface of a young prothallium of tolerably complete form b 
has made its appearance in the middle. ; 
Fig. 11. A more highly magnified view of half such a 
(under surface). 
Fig. 12. A young prothallium, produced by 
thallium (under surface), 
— 
* See ante, page 133. 
distinguishable. 
before the thickened cushion 
prothallium, in which a number of antheridia exist 
budding from the margin of an old sterile (proliferous) pro- 
+ June 1852. 
