IN FLOWERING PLANTS, 155 
its becoming hollowed out and dilated into a sac very short- 
ly after its first appearance. It soon becomes intimately 
united to the secundine, its cavity remaining empty for some- 
time. 
He says elsewhere that its duration is various, being often 
ephemeral, in others again becoming the tercine. This 
tercine either entirely disappears or becomes applied to and 
even united with the secundine. 
In others again, the nucleus remains as a cellular mass, 
which is either pushed back by other growth or by the 
pressure of the inner parts, or as in some becomes converted 
into perisperm. That in the instances of its destruction, of 
its conversion into tercine, of its union with the secundine, 
it generally happens that the ovulum presents interiorly a 
large inner cavity, filled with the water of vegetation. 
He states, however, that in other instances it is of longer 
duration either in its rudimentary form or in that of tercine. 
It is not in my power to corroborate these observations ; all 
that I have seen leads me to suppose, that the changes that 
take place in the nucleus occur at or about the period of 
fecundation. And I am not acquainted with any instance in 
which the nucleus becomes united with the secundine, until 
perhaps long after fecundation. 
Quintine. Sac of the Amnios ; Embryo according to M. 
irbel. 
With M. Mirbel's quintine 1 am unacquainted. In his 
first paper he says that it is not uncommon, and that its 
development is only complete when it takes place in a nucleus 
which has remained filled with cellular tissue, or in a 
quartine of similar structure. He compares it to a fine 
thread, boyau delié, fixed by one end to the summit of the 
nucleus, and by the other to the chalaza. 
In his subsequent memoir, he says he has only been able 
to ascertain its existence in certain species, and he mentions _ 
about six instances. 
