218 APPENDIX. 



drop of water, and cover with a coverslip. Allow a drop 

 of strong glycerine to run in under the coverslip while 

 you watch the sporangia under the low power. Note 

 that the sporangia open as the glycerine reaches them, 

 Make a sketch under high power of a ripe sporangium, 

 shewing the annulus and ripe spores ; and of a sporangium 

 after it has opened. 



iv. Find under the low power and examine under the 

 high power some germinating fern spores mounted in a 

 drop of water. Make a sketch of a single spore and its 

 prothallus, shewing 



a. the spore ; 



6. the rhizoids ; 



c. the prothallus ; 



d. its antheridia ; antherozoids may possibly be found 

 in your preparations. 



v. Mount a small prothallus of a fern in a drop of 

 water, with its lower surface uppermost. Shew, on a 

 sketch under low power, the antheridia and archegonia, 

 also the root hairs or rhizoids, all borne on the thicker 

 central part or cushion. 



vi. Examine a longitudinal section of the cushion of 

 a prothallus bearing archegonia. Make a sketch under 

 the high power, shewing 



a. the neck composed of several tiers of cells and 

 standing out beyond the lower surface of the prothallus ; 



6. the large cell in the lower part and imbedded in 

 the prothallus the egg-cell. 



