FUCUS SERRATUS 207 



1. Barren hairs, which are usually unbranched. 



2. Oogonia, bodies of relatively large size, and oval form, with 

 a thick transparent wall, and dark granular protoplasm : each 

 of these is seated on a unicellular pedicel. 



Observe in the largest of the oogonia that the protoplasmic 

 body may be seen to have undergone division into eight parts 

 (ova), the surfaces of separation being visible as transparent 

 lines. 



XI. Observations on the extrusion of the spermatozoids and 

 ova, and on the process of fertilization in Fucus must be made 

 with fresh material, and will be most successfully carried out on 

 the coast, the best season for it being winter or spring. Those 

 who have not opportunity for this may succeed in making the 

 observations on fresh material sent from the coast, using a 

 solution of Tidman's sea-salt, 5 ounces to the gallon, in place of 

 fresh sea-water. 



If specimens of Fucus serratus be kept exposed to the air 

 for some hours (the period of one tide will suffice), an exudation 

 may be observed from the ostioles of some of the conceptacles : 

 on male plants it will be of an orange colour, on female plants 

 of a dark olive green. 



Taking first the male, mount a small quantity of the orange 

 exudation in a drop of fresh sea-water, and examine it under a high 

 power : it will be found to consist of numerous antheridial cells, 

 separated from the hairs which bore them : they will be seen to 

 be bursting, and setting free their contents, and the following 

 stages of the process are to be noted 



1. The antheridial cell is completely closed, the contents are 

 already divided into numerous elongated bodies (said to be sixty- 

 four in number), each having one or sometimes two brightly 

 orange-coloured globules (chromatophores) : these are the 

 spermatozoids, and they may be seen to be in motion before 

 the antheridium bursts. 



2. The wall of the antheridium consists of two layers, the outer 

 more firm layer (extine) and the inner mucilaginous layer 

 (intine) : observe the extine to burst at one end, usually at the 

 apex, and the contents inclosed in the intine escape from it. 



3. The intine gradually swells, loses its contour, and the 



