of the Organs of Pilularia globulifera. 495 
the germ, which has pushed through the valves. d. One of the 
valves. 
Fig. 14. A more advanced sporule. The mass of cells which constitute the 
germ has here forced its way through the conical projection, which 
is partly dilated and partly ruptured, and lies concealed between the 
germ and the sporule. A few of the cells of the germ have thrown 
out rootlets. 
Fig. 15. In this stage the cells of the germ have assumed a more membranous 
character and a more defined shape; it will, in fact, be found to con- 
tain the rudiments of a root and leaf. à. Four cells, which form the 
quadrangular space mentioned in the description, and probably simi- 
lar to the four projecting cells seen in fig. 12. The rootlets are more 
numerous. 
Fig. 16. A section of the last sporule in outline. a a. The outer coat. b. The 
conical projection concealed by the germ. c. One of the valves. 
dd. The outer cells of the germ, separated from the central mass to 
form a sheath for the leaf and root. ee. The place where the sheath 
and central portion of the germ remain continuous. Jf. The arching 
upwards of the germ by which the cavity of the sporule is enlarged. 
g. The young leaf. h. The young root. i. The first appearance of 
vessels. As the germ grows, these vessels are prolonged into the 
leaf and root. 
Fig. 17. A more advanced germ; the leaf and root are still inclosed in their 
sheath. 
Fig. 18. The leaf and root have at length burst through the sheath. a. The 
sheath at the tip of the root. 
Fig. 19. In this specimen there are two leaves: the sheath has been opened 
to show the bud and the connexion of the parts. aaa. The cut edge 
of the sheath. b. The sheath cut close to its connexion with the 
body of the germ. The germ is hollow as high up as the base of the 
bud. The bud consists of a point, from which the first leaf, having 
a tendency to gyration and a root, are in progress of development, 
concealed by a quantity of hairs. 
