BRYOPHYTES—HEPATICAE 
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then stain sharply in acid fuchsin. This should show the general 
form of the antherozoid, and will usually bring out the cilia. 
The Archegonia. The methods for archegonia are practically the 
same as for antheridia. Too much stress cannot be laid upon the 
importance of carefully selecting the material. Use very small 
pieces, and, before placing them in the fixing agent, trim them to 
such a shape that the position of the archegonia will be known 
accurately even after the pieces are imbedded in paraffin. Since air 
is likely to be caught between the perigynium and the archegonium, 
Fig. 67 .—Marchantia polymorpha: early stages in the development of antheridia; from an 
unpublished drawing by Dr. W. J. G. Land. X600. 
it is worth while to use an air-pump as soon as the material is put 
into a chromo-acetic mixture. With the formalin alcohol solution, 
material is likely to sink promptly and the pump is not necessary. 
For stages like those shown in Figure 68A and B, safranin with 
anilin blue or light green is a good stain and 7 to 10 n is about the 
right thickness. 
For stages .like C, in such forms as Marchantia, where the necks 
are long and often somewhat curved, it is better for general purposes 
to use sections about 15 ju in thickness. If it is desired to obtain 
preparations showing the cutting off of the ventral canal cell, the 
