214 
Notes . 
obvious continuity of the dividing wall with the lateral walls of the 
prothallial chambers, — a continuity which is clearly shown through 
a series of mounted sections of the ovule under consideration, there 
can hardly exist a doubt that the two cavities result from a primary 
transverse division of the cell which would normally become at once 
the macrospore, but which in this instance has given rise to two 
macrospores. It will be remembered that in the normal development 
of this structure as described by Strasburger , 1 the embryo-sac mother- 
cell divides into an upper cell which undergoes a further division, and 
into a lower one which normally becomes at once the macrospore. 
Perhaps the ordinary behaviour of the latter cell is due to the supres- 
sion of a further division, such as would have caused the original 
mother-cell to become the parent of four cells, as in the case of spore- 
formation in the Vascular Cryptogams. If this be so, the present 
exception to the ordinary course of development in Pinus , acquires 
a special interest as affording an example of a mode of spore-formation 
at least analogous with that which obtains in the higher Cryptogams. 
The fact, however, that both of the lower cells develop, instead of one 
of them becoming abortive like the two uppermost cells, shows that 
such a hypothesis should be received with caution, even if the develop- 
ment of the embryo-sac in Gymnosperms were far less uniform than 
is actually the case. 
In some other members of the Coniferae, in Thuja for example, 
several mother-cells are differentiated, but only one macrospore normally 
reaches maturity. It might be suggested that the two chambers in 
this Pinus - ovule have possibly arisen by the development of two 
independent mother-cells, such as are formed in the plant just men- 
tioned, but the intimate connection of the two superposed cavities 
renders a suggestion, which implies anything like an independent origin 
in their case, extremely improbable. But whatever explanation be 
admitted to account for their abnormal character, there can be no 
doubt that the two prothallia have been formed only after the two 
enclosing cells or spores were differentiated. 
J. BRETLAND FARMER, Oxford. 
ON THE SYNONYMY OP ANTHOCOMA FLAVESCENS, 
ZOLL. — A Labiate genus, Anthocoma , was proposed by Zollinger in 
1 Strasburger, Die Angiosperaien und die Gymnospermen, p. 114. 
