8TR0CTCRB. 13 
their way out. The other kind of organ exists in fewer 
numbers, and is called the ' ' ovule." At first it appears 
as a little round cavity in the tissue of the pro-embryo, 
lyirg near its centre, and opening on the under side. In this 
cavity lies a small globular cellule. Sumi.iski states that 
while the ovule is in this state, one or more of the spiral 
filaments enter the cavity, and come in contact with this 
central globular cellule. The mouth of the cavity is 
bounded by four cells which grow out from the general 
surface into a blunt cone-like process ; these cells divide 
and grow out until the ovule exhibits externally a cylin- 
drical form, composed of four tiers of cells, the upper- 
most of which converge and close up the orifice. In the 
meantime, the vescicular head of one of the filaments 
has penetrated to the globular cellule, becomes enlarged 
and undergoes multiplication, and in course of time dis- 
plays itself as the embryo producing the first frond, and 
the terminal bud whence the regular stem is developed. 
Such is the substance of Suminski's statement. 
Hofmeister, who confirms these statements in the main, 
and has distinctly observed the young plant, or rather the 
terminal bud of the new axis produced within the 
" ovule," believes its supposed origin from the spiral fila- 
ment to be a delusion, and regards the globular cellule in 
the centre of the "ovule" as itself the rudiment of the 
stem, the embryo originating from a free cell produced 
within it. Mettenius also, who observed a nucleus 
within the globular cellule, believes the development of 
the embryo to consist in the division of this into two, 
which go on dividing to produce the cellulai scale-like 
structure of the first frond. Mercklin states that the 
spiral filaments swarm round the " ovule " in numbers and 
do penetrate it, though he saw this very rarely ; and 
moreover in the tubular portion of the "ovule," almost in 
every case, he saw, at a definite epoch, certain club-shaped 
granular mucilaginous filaments, and these he has found 
in contact with the globular cellule. He concludes that 
these club-shaped filaments are transformed spiral fila* 
