of the Org^aw* q/'Pilularia globulifera. 495 



the gei-m, which has pushed through the valves, a. 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. a. 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, f. 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, a a a. 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. 



