2 70 Bower. — Some Normal and A bnormal 
some measure the case in the Hymenophyllaceae, to which 
the observations now to be described relate. 
The opinion has long been held that, regarding the series 
of Ferns alone, we find in the family of the Hymeno- 
phyllaceae the closest affinity to the Mosses : thus Presl, in 
1843, expressed the view, previously indicated by Sprengel 
and others, that the Hymenophyllaceae constitute a link 
between these two groups ; his opinion was, however, based 
exclusively upon the characters of the sporophyte, and it 
is only to be expected that prior to the discoveries of Hof- 
meister this should have been the case. It was Mettenius 1 
who first supplied a connected account of the prothallus in 
these plants, and pointed out the similarity which exists 
between the prothallus of species of Trichomanes and the 
protonema of Mosses. Since 1864 little has been done; 
Janczew r ski and Rostafinski 2 wrote a description (without 
illustrative figures) of the prothalli of Hymenophyllum m Tun - 
bi'idgense ; Cramer 3 described certain peculiar gemmae, borne 
together with sexual organs on filamentous prothalli, presumed 
to belong to Trichomanes ; Prantl’s work on the Hymeno- 
phyllaceae 4 is almost exclusively devoted to the sporophyte. 
It is, in fact, only quite recently that a substantial addition 
of well-founded facts has been made to the knowledge of the 
oophyte of the Hymenophyllaceae in a paper by Goebel 5 . 
Even there the prothallus of Hymenophyllum is much more 
fully described than that of Tinchomanes , and in no single 
species can it be considered that we have knowledge even 
approaching to completeness. 
Assuming that readers will have made themselves acquainted 
with the works above alluded to, I may proceed at once to 
the description of observations which I have recently made 
1 Ueber die Hymenophyllaceae, 1864, p. 488. 
2 Sur le prothalle de X Hymenophyllum Tunbridgense, in Mem. Soc. Cherbourg, 
1875. 
3 Denksch. Schw. Nat. Ges. Vol. xxviii. (1880). 
4 Unters. z. Morph, d. Gefasskryptogamen, Heft i. 1875. 
5 Morphologische und Biologische Studien, in Ann. du Jard. Bot. de Buitenzorg, 
vol. vii. p. 74, etc. 
