and Laboratory Methods, 



2519 



with an antheridiophore. Describe both. Is Marchantia hermaphrodite or uni- 

 sexual ? 



11. Under high power study prepared slides of cross sections (cut at right 

 angles to the surface of the disc) of the antheridiophore. Draw an antheridium, 

 showing the wall, stalk, and the numerous minute cubical cells in the interior, 

 each of which will produce a spermatozoid. About how many cells in each 

 antheridium ? How many antheridia in each disc ? Do they all develop at the 

 same time ? Notice the openings to the pockets in which the antheridia are 

 situated. About how many spermatozoids are there produced in one antheridio- 

 phore ? 



12, In case no prepared slides are available, cut free-hand sections, mount 

 in water, and study and draw the antheridia under low and high power. 



l.S. From prepared slides study sections of the archegoniophore. Draw an 

 archegonium, showing the lid cells, the neck, the neck canal, the venter, the 



Fig. 8. — Diagram of Life Cycle of Marchantia. 



oosphere and the incept of the perigynium (incipient perigynium). Draw the 

 venter of an archegonium showing the ventral canal cell and the incipient 

 oosphere. 



14. In case no prepared slides are at hand cut sections of the appendaged 

 disc of the archegoniophore, mount in water, and study the archegonia under 

 low and high power. 



15. If male Marchantia plants with properly developed antheridiophores 

 are protected for several days in such a manner that no water will come onto the 

 discs containing the antheridia, active spermatozoids may be obtained in the 

 following manner. Place a drop of water on the upper surface of the disc and 

 after a short time take it up with a medicine dropper and mount. Under high 

 power numerous motile spermatozoids can be seen, each with two flagella. 

 Study their motion for some time, then stain with a small drop of iodine solution 

 and draw. 



