1 52 Johnson . — On Arceuthobium Oxycedri. 
the viscid cells have become converted into viscine, and, in 
spirit-material, are as broad as the lumina of the cells. 
In many, by no means all, viscid cells the wall presents 
thickening in the form of a double spiral. I have seen side 
by side in different cells a double spiral, a single spiral, and 
annular markings. When fully developed the cavities of the 
cells have each a very thin layer of parietal protoplasm 
enclosing a large quantity of cell-sap. At each end the 
cavities of the cells are dilated (Fig. 12). On its inner surface 
this outermost layer is organically continuous with the rest 
of the endocarp, while at its outer surface it is just as 
intimately connected with the mesocarp, though the con- 
nection is less easily made out. 
I have given this detailed description of the endocarp, 
since the origin Baillon assigns to the viscid cells is es- 
sentially different and at variance with what is known 
of their derivation in other fruits : — ; The surface of the 
ovule presents interesting changes which render the in- 
ternal appearance of the ovule and fruit quite different. 
The most external cells of the ovule grow rapidly and 
produce projecting papillae on the originally naked surface of 
the nucellus. These cells soon become long viscid hairs 
which fill the cavity of the pericarp and have a double spiral 
on their walls. In the end all these soft and viscid hairs lie 
close together and form a kind of pulp which could be taken 
for a continuous parenchyma. It is the nucellus which here 
provides the integumentary covering, it is from it also that 
the internal parenchymatous mass playing the part of the 
endosperm is derived V Striking proof of the incorrectness of 
this view came in quite an unexpected manner. In the 
material I had received from Mr. Carruthers were several 
very young fruits, judging from their size. On making 
sections the cause of their smallness was plain. There was 
no seed at all formed ; the ovarian papilla had died early, and 
though readily recognisable was shrivelled ; nevertheless the 
Baillon, op. cit. on page 142, p. 500. 
