144 DEVELOPMENT OF THE OVULUM 
It may not be amiss here to state the possible number of 
coats existing in the ripe seed. 
The possible number is four— 
1, The coat which almost always forms the testa of the 
seed. 
2. The inner integument or tegmen resulting (chim the 
second coat. 
3. The nucleary membrane resulting from the attenua- 
tion of the nucleus, dependent on the enlargement 
of the embryonary sac. [Nucleus perforate in 
ycas. 
4. And the sac of the embryo itself. 
A greater number of coats may apparently exist as I have 
elsewhere hinted, but this is owing to the development of 
the various layers forming the testa. 
The only instance of the actual existence of 5 coats is in 
Gnetum, the supernumerary coat of which results from the 
permanence of the sudden formation of a coat, produced up- 
wards in the form of a style terminated by a stigma, and 
which is obviously intimately connected with a style in func- 
tions ; i. e. with the completion of fecundation.* 
The supposed cases of existence of an additional coat in 
the vitellus of certain seeds are spurious, this organ being no- 
thing more than the embryonary sac preyented from assum- . 
ing its ordinary form, by the condensation, as it were, of the 
nucleus, owing to the deposition of albumen. 
In Tulipa Gesneriana the embryonary sac is quartine, and 
I believe that the secundine is really the nucleus, at least in 
the figures representing the more advanced stages. 
In Quercus robur the quartine would appear to be the em- 
bryonary sac. 
In Lunaria annua the quartine is the paneke sac. 
In Pisum sativum ditto ditto. 
* See Gnetum, p. 167, which belongs to this place.— Ep. 
