128 



Elementary Biology. 



until shed, is enclosed by, the cell-wall of the cell which 

 arises by division of the central cell. The sperm is a 

 spirally coiled body bearing a tuft of cilia at one end, and 

 having attached to the other a delicate sac containing cell- 

 sap and granules. The sperms according to recent re- 

 searches are produced almost entirely from the nuclei of 

 the daughter cells into which the central cell of the sperm- 

 arium divides. This discovery is quite in harmony with the 



FIG. 56. SPERMARIUM OF Adi ant nut 

 capillus-veneris{x 550). (Sachs.) 



IG. 55. THALI.US OF FERN (DIA- 

 GRAMMATIC). (Prantl.) 



h, root-hairs ; an, spermaria ; ar, ovaria. 



/, tissue of thallus ; a, wall of sperma- 

 rium ; s, sperm with attached sac, b. 



conclusions of many workers in the development of the 

 sperms of animals. 



Theovauum (archegonium) is not unlike the spermarium 

 in general appearance. Like the spermarium also, it is 

 formed from a bud of an epidermal cell, and is morphologi- 

 cally a trichome. As in the moss, it consists of a venter 

 and a neck, but differs from the ovarium of that type in 

 having the venter sunk in and continuous with the general 



