FERTILIZATION AND FRUIT-FORMATION IN CRYPTOGAMS. 



53 



the water. The actual fact is that spermatozoids which come into the vicinity of 

 the spherical ooplasts adhere to them in such large numbers that a sphere is some- 

 times entirely coated with spermatozoids (see fig. 203 *). 



It has also been observed that the spherical ooplasts are set rolling by the 

 adherent spermatozoids, and are thus removed from the places where they pre- 

 viously lay stranded. The fertilizing effect exercised by the spermatozoids, one of 

 <• 



2 '^ ' 



I. -^ 



-a-^ 







i -^ JS 





' M'tf/ -:. ' ':^ 



-Jll 

 Fig. 204.— Fertilization and Fruit-formation in Mucorini, Siphonacece, and Floridece. 



'-* Conjugation and fruit-formation in Sporodinia grandis. ^, 6 Vaucheria sessUis. ' Fruit-rudiment witli trichogyne of 

 Dxidrexnaya coccinea. » Antheridia of the same plant with spermatozoids in the act of abjunction. » Fruit of the same. 

 1-4 X 180 ; ', 6 X 260 ; ',8x400; » X 260. ('-» after Bomet. ) 



which, as it appears, coalesces with the ooplasts, consists doubtless in a rearrange- 

 ment of molecules, and the first outwardly visible result of this rearrangement is 

 the envelopment of the ooplast in a tough cell-membrane. The body must now be 

 considered to be a fruit — a unicellular fruit, which remains unaltered in a state of 

 rest for some time, but at length bestirs itself, and stretching out attaches itself 

 firmly to the ground by means of root-like outgrowths. It then divides and gra- 

 dually develops into a fresh Fucus plant. 



In the two cases just described, the ooplasts are not fertilized till after they have 



