CHARACE^E 415 



as these are not of very constant occurrence, reference should be 

 made with regard to them to the descriptions in text-books. 



VI. The sexual organs are first to be examined in 

 the mature state : mount a leaf, bearing the bright 

 scarlet anther idia, in water, and examine under a low 

 power. Note the position at the node and below the 

 oogonium : the spherical form, and attachment by a 

 very short stalk. Observe also the surface markings, 

 which indicate that the whole spherical wall is made up 

 of eight unicellular shields, of which the four upper 

 are triangular, but the four lower, adjoining the stalk, 

 are four-angled. 



Press gently on the cover-slip : the antheridium will 

 burst, and disclose numerous closely packed anthe- 

 ridial filaments ; each of these is partitioned trans- 

 versely into numerous disc-shaped cells, and contains 

 at maturity a single spiral spermatozoid : the form of 

 the latter can be clearly seen under a high power, and 

 under favourable conditions their escape as free, spir- 

 ally coiled bodies, with two cilia. 



Attention should be paid to the mode of attachment 

 of the filaments to the shields : in a mature antheridium 

 which has been burst by very gentle pressure, observe 

 that an elongated cell, the manubrium, rises from the 

 centre of the inner surface : this is terminated by a 

 head-cell, which supports six secondary heads, and to 

 each of the latter are attached four of the antheridial 

 filaments : their total number is therefore about 200. 



The development of the antheridium, or "globule," may be 

 readily followed in the young bud by careful teasing out of its 

 parts, and treatment first with potash, and subsequently with 



