MARCHANTIA. OOPHORE. 23 



above mentioned, treat with potash solution, and warm gently 

 over a spirit-lamp : the bodies are not dissolved, but partially 

 lose their highly refractive quality, without swelling. Treat 

 other sections first with alcohol, and then with ether : wash from 

 the ether with alcohol, and mount : the oil bodies will have been 

 dissolved. 



d. At the lower surface of the thallus may be seen 

 attached organs of two kinds 



i. Hairs, or rhizoids, which are long and unicellular, 

 and are inserted deeply in the tissues of the thallus : they 

 often show dotted or peg-like ingrowths of the cell- wall 

 of various form. 



ii. The amphigastria, which may now be seen to 

 be plates of tissue one layer of cells in thickness : their 

 cell- walls are often coloured violet or brown. 



Returning now to the "stomata," note under a 

 high power their structure as seen in a good transverse 

 section : each will appear as consisting of tiers of small 

 cells (four or more in depth), which surround a large 

 central cavity. 



IV. Cut tangential sections so as to strip off the 

 so-called " epidermis " : mount with the outer surface 

 uppermost in weak glycerine : observe under a low 

 power the diamond-shaped areas above described, and a 

 single large " stoma " in the middle of each. Under a 

 high power note 



1. That the cells of the " epidermis" contain 

 chlorophyll. 



2. That each "stoma" is bounded by four or five 

 of the tiers of cells above described. 



3. That these cells contain but little chlorophyll. 



4. That on focusing downwards it becomes apparent 



