Fertilization in Pinus Slrobus. 445 
absent from the nucleus. The reticulum, on which the chro- 
matic substance is disposed, presents numerous aspects, as 
already indicated in the description of this nucleus during 
its period of growth. Under very high magnification, it does 
not show, in normal conditions, a true granular structure ; but 
it may present a most delicate, interrupted, granular network ; 
or it may consist of large, irregular, diffusely staining masses 
which are united into an imperfect reticulum (Figs. 37^ and 
37^*). In the latter instance the chromatic granules are either 
too minute to be distinguished, or they have been dissolved 
in the linin ground-work. The linin, always very abundant 
in this nucleus, may form heavy hyaline cords, on which the 
chromatin is collected at irregular intervals (Figs. 37 ^ and 
37 /) ; but it more often consists of less conspicuous strands 
(Figs. 37^-37^). Great as the variations are in the structure 
of this nucleus, its chromatin has always been found, in the 
species of Pines studied by the writer, to exist either in the 
form of irregular granules of varying sizes or apparently dis- 
solved in the linin. Such a resolving of the chromatin into 
nucleoli as that described by Chamberlain (’99) in Pinus 
Laricio and illustrated in his Figs. 14 and 15 has not been 
observed. 
Whether the various appearances presented by the egg- 
nucleus represent normal phases in its life-history, or whether 
one is normal and the others artefacts resulting from the 
action of fixing agents, is, of course, a mere matter of con- 
jecture. But inasmuch as these different aspects are cha- 
racteristic of this nucleus during its period of growth, also 
after it has to all appearances reached maturity, and again 
at the time of its conjugation with the sperm-nucleus, it 
seems reasonable to conclude that all are normal and cor- 
respond to certain physiological activities which take place 
within the nucleus. 
Strasburger (’84) described the nucleus of the oosphere in 
the Abietineae as being densely filled with' a granular sub- 
stance, which entirely obscured or masked the chromatin. 
This substance he called metaplasm, and virtually considered 
