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 4 ). 



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 



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



'-* Conjugation and fruit-formation in Sporodinia grandis. 6 , Vaucheria sessilis. 7 Fruit-rudiment with trichogyne of 

 Dudresnaya coccinea. 8 Antheridia of the same plant with spermatozoida in the act of abjunctiou. Fruit of the same, 

 i-* x 180 ; , x 250 ; ?, 8 x 400 ; x 250. (*- after Bornet. ) 



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 



