BUYdPllM'KS 



305 



£jlolral:ir lioily (Figs. 377, 378). A section tlirongli this 



body shows it to consist of a single layer of cells, which 



forms the wall of the antheridiuiii, ami 



within this a comjiact mass of small 



euljical (square in section) cells, within 



each one of which there is formed a 



single sperm (Fig. 37S). The sperm is 



a very snudl cell with two long cilia 



( Fig. 377). These small biciliate sperms 



are one of the distinguishing marks 



of the Bryophytes. When the mature 



antheridia are wet they are ruptured at 



the apex and discharge their contents 



(Fig. 277), and the sperms escaping 



swim actively about. 



I'M. The archegonium. — This name 

 is given to the female sex organ, which 

 is a many-celled structure, shaped like 

 a flask (Figs. 377, 3S7). The neck of 

 the flask is more or less elongated, and 

 within the bulbous base (renter) the single egg is organized. 



To this neck the swimming s}ierms are attracted, enter 

 and pass down it, one of them fuses with the l'i:'^, and this 

 act of fertilization results in an oospore. 



300. Germination of the oospore. — The oospore in I5ryo- 

 plivtes is not a resting spore, l.mt germinates immediately 

 liv cell division, forming the sporophyte embryo, which 

 l^resently develops into the mature sporophyte (Fig. 379, A). 

 The lower part of the emliryo develops downward into the 

 gametophore, forming the foot, Avhich penetrates and ob- 

 tains a firm anchorage in the gametophore (Fig. 370, /?, ('). 

 The upper 2iart of the embryo develops upward, organizing 

 the seta and capsule. In ti'uc flosses, when the embryo 

 becomes too large for the venter of the archegonium in 

 which it is developing, the archegonium is Ijroken near the 

 base of the venter and is carried upward perched on tlie top 



;. i;78. .-VntlR-fidiiim of 

 a lix'Crwnrt in section, 

 bhowiiiL,' siiii^le layer 

 rif wall cells surround- 

 inir the mass of moth- 

 er cells. — After Sxr.AS- 



EUIO.EK. 



