438 MR. W. C. WORSDELL ON THE 
plants. As our knowledge of the anatomy of the Cycads is at 
present somewhat meagre, it seems desirable to record any 
fresh observations on the internal structure of plants of that 
order even when that structure is of a comparatively normal 
type. 
CYCAS REVOLUTA, Thunb. 
Young Seedling*. 
I examined two young seedlings of this plant. The chief 
points in their structure, to be described below, are the vernation 
of the cotyledons, the structure of the vascular bundles of the 
latter, the connexion of these bundles with the stem, and the 
extrafascicular vascular structures of the hypocotyl. In one of 
these seedlings the plumule is scarcely as yet visible between 
the stalks of the cotyledons, and the radicle still quite short 
(Pl. 20. figs. 1 & 2). The other seedling is somewhat older, the 
plumule having grown out, bearing two conspicuous scale-leaves 
which almost completely enclose it (figs. 3 & 4). The hypogeal 
cotyledons are united together and embedded in the'endosperm of 
the megasporangium (fig. 3) : they are thick and fleshy ; the two 
together, united by their ventral surfaces, are round in contour, 
as seen in transverse section. They separate at the tips, as they 
do below in the stalk. Each cotyledon has, morphologically, a 
conduplicate vernation: this is proved, first, by the arrange 
ment of the bundles in a A-shape, the open part of which Is 
directed towards the ventral surface ; secondly, by an indication, 
in the free tip of the cotyledon, as seen in transverse section, of 
the place of union of the two folded portions of the lamina bya 
line of cells, smaller in size and with more conspicuous nuclei 
than the rest, extending a short way inwards from the ventral 
face; one of the two lobes thus formed is considerably larger 
than the other. Some endosperm extends part way along the 
ventral surface of the organ. 
The A opens out more or less markedly in the tip of the coty'e 
don, as also below in the lower part of the stalk, regione where 
the organ becomes more flattened and less angular m shapa 
lhe cotyledons, except at the tip, are completely connate a? 
; of 
are not easily separable. In transverse section the place i 
union of the two is indicated by two rows of cells running a 
Leaf in Vascular 
* Cf. Bower: “On the Comparative Morphology of the 
Cryptogams and Gymnosperms,” Phil. Trans. vol. 175. 1884, p. 583. 
