15z NOTICES OF BOOKS. 
containing a highly refringent nucleolus, is formed a transparent zone 
marked with radiating strie ; on the outer border of this zone bf es 
free cells; they each develope a lateral outgrowth which ahaa 
into the endosperm a and divides at its extremity, and it is this ter- 
minal cell which gives origin to the first foundation of the embryo 
fig. 3). 
; ae Ginkgo biloba disappearance of the nucleus of the oosphere is 
followed by the formation, by protoplasmic condensation, of more 
than 30 new nuclei. Round each of these a cell-wall is formed as 
in iat and the whole mass of cells unites to give origin to a 
single embryo. 
Absorption of the nucleus inthe oosphere of Picea vulgaris (fig. 
4)is usually followed by the simultaneous appearance of 4 new 
nuclei at its organic apex (structural base). Soon after this other 
sep 
we shall call the cell-band (Zelipla ioe A new nucleus is formed 
from each polar condensation, and the cell-band becomes divided so 
that each division og the protoplasmic wall of a new cell (fig. 6). 
{t only remains now for cellulose to secreted on these walls, and 
the new cells are complete. By a ymca _Broeaee there are formed 
three series of cells in the oosphere of a. 
It was found, in working with ibiregyre orthospira, that division 
could be delayed until morning, by submitting the specimens to a 
lower temperature. en division is about to occur the nucleus 
(fig. 7) begins to enlarge, and its nucleolus 579 a 2 the equator 
of the latter is then seen to be provided with an rupted band 
(nucleus-band) formed of sina rods like those we ae already seen 
Picea (fig. 8). Currents of protoplasm containing starch-grains 
nucleus, a ring of edie 3 is saa to extend round the cell, towards 
which ring the starch-grains eed in great numbers. It is on this 
— that the first eee eer of ceitatons takes place at the expense of the 
— while, the nucleus has become barrel-shaped, and 
a mass of erenla 61 protoplasm has collected at each of its poles. The 
nleus-band begins to divide a quarter of an hour after its first appear- 
e (fig. 9); all this time the nucleus has been gradually increasing 
in npc and at this aes it shows some activity, poising itself now in 
one direction and now in another. ven minutes after commence- 
ment of division in ‘the oe by which time the nucleus has 
attained one-and-a-half tim ea ieaginad olen; the walls of the latter 
