

1905.| Lagenostoma, a Type of Pteridospermous Seed. 257 
degree have been analogous to the carpellary investment of Angiospermous 
‘seeds. In the latter case, the functions of the carpels are manifold. Not 
only do they contribute in a marked degree to the pollination mechanism of 
the seed, but at least one of their other functions is to serve as protections to 
ithe developing ovules. The latter would seem to be the earlier and more 
primitive of the two, for in these Lagenostomas the protective function 
of the “cupule” is probably the main service which it performs, although 
a suspicion is not wanting that even here, where the “cupule” takes 
no direct part in pollination, it may have been of importance indirectly in 
furthering the act of fertilisation.* Thus, while offering no suggestion as to 
homologies, which may or may not exist between these two types of seminal 
investment—a question which in the present position of our knowledge of 
these fossil seeds we are hardly warranted in discussing—it can scarcely 
‘be doubted that the function of the “cupule ” was in part at least that of a 
protective investment, and that the organ was in this respect analogous to the 
carpels of the higher plants. 
At the present time, we are acquainted with the manner in which the seeds 
were borne in the Pteridospermee in one instance only. The material on which 
ithe correlation of LZ. Lomaxi with Lyginodendron was based, did not afford any 
direct evidence of this nature. But in the specimens recently described by 
Mr. Kidston, organic continuity existed between the foliar and reproductive 
organs. It was shown that, in some Medullosee, large seeds terminated 
an ordinary frond of the Neuropteris habit, with pinnules in all respects 
‘similar to those of the sterile fronds of that genus. 
The new specimens discussed here unfortunately yield no direct evidence as 
to the type of sterile frond associated with these seed-bearing axes; which 
themselves, apparently, did not bear foliar organs. The presence of detached 
pinne of Sphenopteris obtusiloba, which occur with both these seeds (Plate 1, 
photo. 2), is, in itself, quite without any reliable value as an indication 
of the character of the foliar organs of the plants to which these seeds 
belong. But the general morphology of these branched axes indirectly affords 
some evidence on this point, andin Lagenostoma Sinclairt, and possibly also in 
L. Krdstoni, we have the first clue to the habit of the Lyginodendre as regards 
the manner in which the seeds were borne. 
In discussing the nature of the seed-bearing axes, it was pointed out 
(p. 254) that they are best regarded as portions of a highly-compound frond 
with reduced lamina. In the case of Z. Kidstoni, although the long rachis- 
like structures do not afford any conclusive evidence on this point, they 
nevertheless present many points of morpholcgical similarity to the sterile 
* Oliver and Scott, zbed., footnote, pp. 214, 215. 
