the more primitive type in the Ferns f 1 1 9 
cussed appears to rest on very slender grounds, and it may 
well be asked whether some alternative opinion may not be 
more probable. May we not find a more true affinity to the 
lower forms in the Eusporangiate Ferns? In discussing this 
question I propose to take a general survey of the supposed 
affinity. In view of the wide differences between the Bryo- 
phyta and the Pteridophyta, and of the great antiquity of the 
Ferns, it will not be desirable to compare directly any one 
living Filicineous type with any one living type of Bryophyte, 
but rather I would consider the more general question of pro- 
bability of the Eusporangiate character being primitive and 
ancestral as compared with the Leptosporangiate. It may be 
noted, however, that on general comparative grounds the 
affinity of the Eusporangiate ferns would be to the Liverworts 
rather than to the Mosses, and the question may therefore 
resolve itself into this : whether the affinity of the Lepto- 
sporangiate Ferns to the Mosses, or of the Eusporangiate 
Ferns to the Liverworts, be the more true and natural one. 
Looking at the question then in its broader aspect, it will 
be noted that of the three great phyla of Vascular Crypto- 
gams, two are exclusively Eusporangiate. There is no 
evidence, either from present or fossil forms, that the Lycopo- 
dinae or Equisetineae have had any Leptosporangiate ancestry, 
and they therefore serve to show that a stock may be Euspor- 
angiate from the first, and make it also the less probable that 
the Ferns should have originated otherwise. The absence of 
any intermediate steps leading to the Leptosporangiate type, 
except from the Eusporangiate Ferns themselves, adds weight 
to this argument. 
In the second place, the more bulky type of sporangium is 
already foreshadowed by the capsule of the Liverworts ; it 
would be going too far to say that the capsule of a J linger- 
mannia or of a Mar chan tia is one Eusporangiate sporangium, 
for it is probable that in the evolution of the Ferns a sub- 
could come about, will hardly commend itself to the reason as in any way probable. 
Moreover, it is not apparent on other grounds that there is any near affinity between 
the Anthoceroteae, and the Filmy Ferns. See Prantl, Hymenophyllaceae, p. 62. 
