MARCHANTIA. OOPHORE. 29 



a. The "stomata," of similar character to those on the vegetative 

 thallus. 



b. The pores or openings of the cavities in which the antheridia 

 are seated. These pores are of about the same size as the 

 " stomata," but differ from them in being often triangular, and in 

 the number (nine) and arrangement of the surrounding cells. 



The Female Branch (ArchegoniopJiore). 



XI. Remove the star-shaped head of a female branch 

 which has attained a considerable length, and examine 

 first the upper surface : with the naked eye or with 

 a lens note the rounded arms, nine in number, and 

 the diamond-shaped areas, each having a single central 

 stoma. 



Turn the head upside down, and observe on its lower 

 surface 



1. The central attachment or stalk. 



2. The radiating arms, usually nine in number. 



3. The curtain-like perichaetia, which alternate in 

 position with the arms : the archegonia are enveloped 

 by these, and if the branch be an old one 



4. The nearly spherical sporogonia may be observed 

 protruding from them : if these be fully ripe, they may 

 have burst, in which case a yellow flocculent mass may 

 be seen protruding from them, consisting of the spores 

 and elaters. 



XII. Cut transverse sections of the stalk, and mount 

 in glycerine : examine under a medium power, and 

 compare with similar sections of the stalk of the 

 male branch : the general arrangement of the parts 

 is the same, the chief differences being in this case 



1. The quadrangular outline of the sections. 



