MI KALES 



503 



as malic acid, into water serves as a guide, the spermatozoida moving 

 towards the centre of diffusion. Probably it is in this way that ti 



A 



Fig. 3Q5. 



Fertilisation in Onoclea sensibilis : the arrows indicate direction to the growing 

 point. A =a vertical section through an archegonium probably within ten minutes 

 after entrance of the first spermatozoid. ( x 500.) B = vertical section of the venter 

 of an archegonium, containing spermatozoids, and the collapsed egg with a sperma- 

 tozoid within the nucleus. Thirty minutes. ( x 1200.) (After Shaw.) 



are attracted to the neck of the archegonium, which thev mav be 

 seen to enter, and finally one spermatozoid coalesces with the ovum 



Fig. 396. 



Horizontal section of an egg, showing coiled male tmcleos within the female. Twelve 



hours. ( . 1200.) (After Shaw.) 



(Fig, 395). Fertilisation is effected by entry of the male nucleus into 

 the female nucleus, and their complete fusion (Fig. 396). Thus the 



