MARCHANTIA POLYMORPHA. 73 



a. The rapid motion of the antherozoids, becoming 

 slower and slower until after some time they come 

 quite to rest. 



b. Their form a slender filament, at the anterior end 

 of which may be detected,when the motion becomes 

 sufficiently slow, 



c. Two very delicate vibratile cilia; the form and 

 motion may be more readily studied by staining 

 with iodine, and watching the antherozoids as they 

 pass gradually under its influence. 



d. The delicate hyaline vesicle and its contents, 

 dragged about by some of the antherozoids 

 until finally detached. 



If the section be from an alcoholic specimen, some an- 

 therozoids will have escaped, or can be made to escape by 

 pressing on the cover-glass, when the form can be studied 

 as before, but the filaments will be found quite closely 

 coiled, the cilia difficult to detect, and the vesicle probably 

 invisible. 



F. THE ARCHEGONIAL BRANCH. 



i. The pedicel ; in a transverse section under low 

 power, notice 



a. The general outline. 



b. The two grooves. 



c. The posterior plate containing air cavities and 

 chlorophyll tissue. 



d. Illustrate with diagram. 

 Under high power, notice 



e. The larger rounded anterior part, in every essential 

 like that of the antheridial pedicel. 



/. The smaller flattened posterior part in which lie 

 i. The air cavities, like those of the thallus, ex- 

 cept smaller, sparsely provided with 



