that all of the spores studied in the Iowa species are of 
a single type and size, bearing a normal tetrad scar which 
certainly indicates a homosporous eusporangiate fern, 
and we have not observed the slightest evidence of en- 
dosporal development. The degree of preservation is not 
as good as desirable—no fossil ever is—but such contents 
as are preserved in some of the spores appear to have 
been non-cellular. 
There are several important questions relating to the 
Coenopterids which at this time suggest themselves. As 
yet we are not in possession of facts sufficient for satis¬ 
factory answers. 
Is this massive fructification a strobilus? The ferns 
are non-strobilar, but here is a much-branched axis con¬ 
structed, not on a pinnatifid, but upon a radial plan. The 
pyriform sporangia are pedicellate. It is true that Stau- 
ropteriSy a still more “primitive” Coenopterid fern is 
radially symmetrical and bush-like but the sporangia are 
believed to have been borne terminally in small lax clus¬ 
ters (3). 
If the fructification is strobilar,or “pseudo-strobilar”, 
what is its possible relationship to the pteridosperms? 
One of the fundamental gaps or “missing-links” in our 
knowledge of the earliest gymnosperms is their degree 
of kinship with the filicinean pteropsids. 
In any case, this unique structure among the ferns, 
now partially understood, will reshape our conception 
of the Coenopterid ales. That they were a very diversified 
group is well-known. How diversified is still a matter for 
speculation, but with certainty more than any of us have 
supposed. 
[ 164 ] 
