Notes on Fossil Fungi . 5^ 
the more or iess conical lid being prevented from projecting out 
wards had become invaginated into the cavity. 
DESCRIPTION OP THE FIGURES ON PRATE IV. ILLUSTRATING 
F. W. OLIVER’S NOTES ON FOSSIL FUNGI. 
FUNGUS ON ALETHOPTERIS. 
P'ig. 1.—Section of a portion of a pinnule of Alethoptcris aqiiilina cut 
parallel to the surface. At a one of the pockets filled with 
fungal spores is cut through, x 50. 
Fig. 2.—Vertical section of part of a pinnule; the midrib is on the 
extreme right, a, b. c and d, the receptacles of the fungus, 
x 20. 
Fig. 3.—Cross-section of another pinnule ; a and b fungal receptacles, 
x 20. 
Fig. 4. — Part of the boundarj 7 wall and a few spores from one of these 
receptacles. The spores appear to be attached to hypliae 
coming from the wall, x 625. 
Fig. 5. A single spore, x 1250. 
FUNGAL SPORANGIA FROM SEEDS. 
F'jg. 6.—Thret sporangia in series, from the nucellus of Polylupfiospcr- 
tnum resembling those belonging to Grilletia, Renault and 
Bertrand, x 600. 
Fig. 6a.—Another detached sporangium from the same source. 
I<’ig, y. —Portion of the wail of the nucellus of Stephanospermum caryoidcs 
cut in longitudinal tangential section, nnv, wall of macrospore; 
t, tracheal sheath of nucellus; up, remains of parenchyma of 
nucellus; e , nucellar epidermis; a, b, c , supposed sporangia of 
a Grilletia -like fungus, x.85. 
Figs. 8, 9, 10.—T liree examples of the supposed sporangia, 8 and 10 
shew the oval operculum with its characteristic furrow (a) ; in 
9 the supposed operculum ajjpears to have been ground awa) r , 
but traces of the furrow remain. The cells upon which the 
oval bodies lie belong to the parenchyma of the nucellus. 
x 850. 
A CONVENIENT FORM OF POTOMETER. 
[Text-Fig. l.J 
rpHE apparatus that forms the subject of this note does not lay 
j claim to any special originality, and is merely a convenient 
modification of a form that I have used for a number of years. 
The corked bottle is provided, preferably, with an india-rubber 
cork with three holes bored through it. One of these takes the 
bent glass tube (t) which has a fairly fine tubulus, such as is 
ordinarily used for a potomcter. It is important that this tube 
should not project beyond the lower surface of the cork, as other¬ 
wise any air that may accumulate, or be present, above the water 
inside the bottle cannot easily be got rid of. 
