FUCUS. 57 



VIII. Cut transverse sections through the fertile 

 branches of the thallus, so as to traverse the mature 

 conceptacles : mount in glycerine, and examine under a 

 low power. Take first sections of the male thallus, and 

 having found a point where a male conceptacle has been 

 cut in median section (i.e. so as to traverse the ostiole), 

 note 



1. The spherical, or flask-shaped cavity. 



2. The ostiole, by which the cavity communicates 

 with the exterior. 



3. The hairs, which almost fill the cavity, and may 

 even protrude through the ostiole. 



4. The antheridia, which are single oval cells, borne 

 often in large numbers, on these hairs. 



It may be further noted that the cavity is lined by a 

 small-celled tissue, from which these hairs arise, and 

 that this graduates imperceptibly into the other tissues 

 of the thailus, which are similar to those of the purely 

 vegetative parts. 



IX. Tease out with needles the contents of a male 

 conceptacle in glycerine, mount, and observe under a 

 high power : note 



1. The thin, colourless, branched hairs, which bear 

 the oval cells (antheridia) with their yellowish granular 

 contents. 



2. The mode of branching of the hairs which bear 

 the antheridia. 



3. Long hairs, branching less frequently, or not at 

 all ; these do not bear antheridia. 



X. With the above, compare sections cut through 

 female conceptacles, mounting as before : in its form, 

 and also in its relation to the tissues surrounding 



