MetapJiyta Fucus. 87 



spermarium. Scattered amongst the male hairs are other 

 hairs, which are unbranched, but destitute of spermaria. 

 These are sterile hairs, which have been unable to develop 

 into true sexual hairs owing to the pressure for space, etc. 

 Some of these sterile hairs are very long, and extend out 

 through the mouth of the sac to the exterior. 



The ovaria are comparatively large spherical bodies rest- 

 ing on a basal cell which arises from the lining-wall of the 



FIG. 25. Fncus vesiculosJis. (Thuret.) 



A, branched hairs bearing spermaria. a,. J3, sperms. //, ovarium (outer 

 wall, a ; inner wall, i) containing eight ova. ///, ovum surrounded 

 by sperms. J V, V, development of embryo. 



sac. Each ovarium consists originally of a cell-wall which is 

 composed of an inner and an outer layer, filed with dense 

 dark protoplasm. The ovarium in F. platycarpus divides 

 into eight ova, although in other forms a smaller number of 

 ova are occasionally formed from the contents of each 

 mature ovarium. The ovarium on bursting ejects its ova 



*G 4 



