Notes . 
213 
sepals ; but against this it may be said that the somewhat fleshy con- 
sistence, which characterises the reduced labellum, renders it difficult 
to see how one can account for its small size on this supposition, 
since its actual shape demands more room than if it had developed 
normally. On the whole, then, the former hypothesis seems the more 
likely one, namely, that the diminution of size of the labellum is the 
result of the occurrence of the pollen-sac or sporangium upon it; and 
this view is borne out by many other teratological facts connected with 
the abortion or alteration of ovules and pollen sacs in other flowers, as 
well as by the characters of fern-sporophylls, whenever they differ 
from the vegetative leaves. 
J. BRETLAND FARMER, Oxford. 
ON THE OCCURRENCE OF TWO PROTHALLIA IN 
AN OVULE OF PINUS SYLVESTRIS.— The diagram which 
accompanies this note represents a some- 
what remarkable abnormality in the 
development of the ovule of Pinus 
sylvestris ; and as I have not met with 
any notice of a similar case, either in 
this plant or in any of its immediate 
allies, it seemed worth recording. The 
abnormality consists in the occurrence 
of two distinct endosperms or prothallia 
in the same ovule. They are separated 
by a well-marked wall, which runs obli- 
quely between them and is continuous 
with the lateral walls of the cavity con- 
taining them. The upper prothallium 
(that nearest the micropyle) is somewhat 
smaller than the other one, but both 
possess perfectly developed archegonia 
(a, in the diagram), and the protoplasm 
of the central cell in each archegonium 
exhibits the frothy vacuolation charac- 
teristic of that of a normally formed Fig. 5. 
corpusculum. 
The question arises as to how the two chambers, in which the 
prothallia respectively lie, have been formed. Judging from the 
