

IN FLOWERING FLANTS. 179. - 
The outer coat by its gradual increase, at length likewise 
encloses the nucleus and the body of the second integu- 
ment, (exceptions occur in Ricinus, etc.) not unfrequently it 
entirely encloses this latter. 
Throughout the above period the nucleus has continued 
to increase in size, generally it becomes completely covered 
by one or both coats, in other instances again, its apex pro- 
jects beyond the openings of these, to a greater or less extent. 
At the time of fecundation an ovulum will generally be 
found to consist of an outer coat, open at its true apex; (the 
opening varying in size, but being always less than the dia- 
meter of the body of the ovule;) of an inner cellular coat, ge- 
nerally thinner than the outer, prolonged beyond the nucle- 
us in a hollow neck, the apex of which is more or less dila- 
ted and occasionally almost fimbriated, and which is generally 
on a level with the mouth of the opening of the outer coat, 
occasionally, however, projecting beyond it, even to a consi- 
derable distance. 
Lastly, of a central cellular body, the nucleus, generally 
more or less ovate; its apex more or less conical, being 
9f a more lax tissue than the remainder, and projecting occa- 
sionally beyond the opening in the coats of the ovulum. 
This body will, at the period alluded to, generally present 
a central discoloured nucellus, or frequently even an excava- 
ted sub-central cavity of variable dimensions. The discolor- 
ation alluded to, or rather opacity, is invariably the precursor 
of the cavity that is to be formed, and which is generally form- 
ed from below upwards. 
The ovulum at this period may be entirely cellular, or 
it may be variously supplied with vessels, but on this point 
I shall remark more fully when speaking of the raphe. 
The opening of the integuments may be variously situated, 
either directly opposite to the point of attachment of the 
ovule, or at one side of it. Of this latter instance, there are 
two modifications. I shall have occasion hereafter to revert 
to this subject. 
