3 86 
MONTGOMERY ,. 
[Vol. XV. 
deeply stained, and change into globular colloid-looking masses 
with a central more deeply stained spot. I propose to call these 
bodies paranucleoli, because of their origin they may always be 
found in the micropylar nucleus and occasionally also in the 
antipodal nucleus.” When these nuclei begin to conjugate, 
the large nucleoli of both fuse to form the single nucleolus of 
the primary endosperm nucleus ; at the same time a new struc¬ 
ture makes its appearance, in close contact with the nuclear 
membrane of the primary endosperm nucleus : “ This body . . . 
corresponds, I believe, to the nucleolar membrane of the 
antipodal nucleus” ; it; is at first granular, later homogeneous. 
Still other, smaller spherical bodies later appear in the nucleus, 
which may have some connection with the paranucleoli. Finer 
structure of the nucleolus: in the nucleolar membrane “ a 
number of very minute dark radially placed pores or striae can 
be observed, and . . . these striae are continued into very 
delicate cilia-like fibrils radiating out from the nucleolar mem¬ 
brane into the nuclear hyaloplasm. . . . The nucleolus is 
differentiated into an outer zone and an inner zone. The outer 
zone is less deeply stained, and on careful examination is found 
to be made up of a circle of peripheral endonucleoli, which are 
slightly elongated radially. The inner zone of the nucleolus 
is very darkly stained, and shows a number of large and irregu¬ 
larly disposed endonucleoli.” The structure of the nucleolus 
may be somewhat different in other stages of its development, 
thus it may be composed of “ (i) A thin unstained nucleolar 
membrane; (2) a great number of peripheral endonucleoli; (3) 
a deeply stained, apparently structureless, layer; (4) a corona 
of minute, slightly elongated, endonucleoli surrounding (5) a 
large central endonucleolus. ... In a resting cell, . . . the 
center of the nucleolus is occupied by a large endonucleolus, 
which sends out minute fibrils through the nucleolar sub¬ 
stance. ... I believe the endonucleolar fibrils probably to pass 
through the finer pores in the nuclear membrane”; and Mann 
conjectures that ‘‘the endonucleolar filaments constitute the 
linin element of the chromosomes.” Functions of the nucle¬ 
olus: it is “concerned in the assimilation of food-material.” 
He holds “the nuclear chromatin to be less highly elaborated 
