64 
HISTOLOGY OF VEGETABLES. 
Transverse section of Ivory-nut. 
FIG . 47 . so many radii, are seen; their 
dilated ends are well shown, 
also the fact of their non- 
communication with adjoin- 
ing pores, and the presence 
of the cell wall. 
In specimens mounted in 
preservative liquids, the ca~ 
naliculi and central cavities 
become filled with the fluid ; 
but those mounted in a dry state contain air, and the 
points above mentioned are more clearly shown, as 
both cavities and canaliculi are perfectly black, and 
they have precisely the appearance of bone cells, the 
surrounding parts being transparent. 
The outer coating or husk of the Ivory-nut is of a 
brown colour, and exhibits a 
structure quite different from 
that of the white interior. Some 
of the cells, as shown at a, in 
Fig. 48, are, when transversely 
divided, of hexagonal figure, and 
consist of a small central cavitv, 
«/ ' 
with a very great number of 
minute equal sized pores or ca- 
niculi radiating from it towards 
the wall of the cell. In imme- 
diate connexion with these cells, as shown at b , are 
others divided longitudinally, in which the system of 
FIG. 48 . 
wgwm 
Vertical section of the 
testa, or husk of the Ivory - 
nut . 
