EOCKWEED 295 



conceptacles ? Do you ever find oogonia and 

 antheridia in the same conceptacle ? 

 Draw the section as seen under the low power, and 



the conceptacle and a single oogonium as seen under 



the high power. 



PHTSIOLOGT 



a. The fertilization of the oosphere. — From plants that 

 have been hanging in the air collect a drop of 

 the orange-colored fluid that exudes from the male 

 conceptacles. Mix this drop with a drop of sea 

 water and examine under the high power. Note 

 the antheridia floating in the drop. Look for 

 antherozoids actively swimming about. What 

 is their shape? Color? Structure? By what 

 means do they swim ? Apply a drop of iodine if 

 necessary. Are they at all like the antherozoids 

 found in Chara'i Draw. 



Mount in a similar manner a drop of the olive- 

 colored fluid issuing from the female concepta- 

 cles. Look for oogonia. Try to find an oogo- 

 nium whose wall is dissolving, thus setting free 

 the oosph.eres. Do the oospheres change in 

 shape before being liberated ? What is their 

 structure? Can you detect a nucleus? Have 

 they any means of locomotion ? Draw. 



After finding some mature oospheres, mix on 

 the slide with the water containing them a drop 

 containing antherozoids. Study the behavior of 

 the antherozoids and try to see as much as pos- 

 sible of the union of two kinds of cell {fertilizor 

 tion). Draw. 



