F. W. Oliver 
64 
annulus is Sturiella, Weiss (Pccoptcris intermedia of Renault), the 
sporangia of which Solms-Laubach 1 says are especially distinguished 
“by the presence in their wall of an apical group of abnormally 
thick-walled cells which extend some way down on the outer side of 
the sporangium; these cells have quite the appearance of an 
annulus.” But in addition to this character there is a supposed 
peculiarity of the cells of the annulus, which Renault places on 
record' 2 in his original description of the specimen. He says “Les 
cellules qui composent le connecticule [?'. e. the annulus] sont 
irregulieres; leurs parois fortement incrustees presentent des stries 
transversales ou des reticulations (fig. 10).” The figure in question 2 
is a somewhat tangential longitudinal section of a sporangium, and 
in the position at which an inner layer to the wall (did such exist) 
would be exposed, three spindle-shaped cells are shewn with 
transverse striate markings. Without examining the original 
preparation, I should, however, hesitate to put any interpretation 
on these appearances other than that sanctioned in the passage 
quoted from the text. 
Whilst admitting the possibility that my sporangium might be 
placed near this last type—should it bear the interpretation just 
suggested—I am inclined to associate it with the Botryopteridea?, 
indeed, it may be a sporangium of Botryoptcris forensis , B.R., 
revealed in a new light owing to a fortunate accident of fossilisation. 
Such an attribution would receive a certain measure of corrobora¬ 
tion from the fact that throughout the small block from which the 
preparation was obtained, the very characteristic equisetiform 
hairs of B.f°rensis are sparsely scattered. That the dimensions of 
the cross-section (.65 mm. x .53 mm.) are somewhat below the 
normal for this species may be due to the fact that our section is 
not across the broadest portion of the sporangium, or possibly, it 
may not yet have attained its full dimensions. The smallness of 
the spores (.02 mm. diameter) is also susceptible of explanation in 
view of their immaturity and of the contraction which they have 
undergone. 
The biological significance that may be attached to the 
tracheal mantle may well be that of an organ for the conveyance to 
the maturing spores of adequate supplies of water. That such a 
provision has not been more generally recognised is not on the 
bSolms-Laubach, Fossil Botany, Bug. Edn., 1891, p. 145. 
2 Renault, Cours de botanique fossile, tom. iii., p. 123. 
3 Loc. cit., plate xxii, fig. 10. 
