134 



THE PLANT CELL. 



being the so-called ventral canal-cell, the other two being the 

 neck canal cells. 



Fig. 102. — Diagrams showinc the foemation of the Akcheqonia in 

 THE Embbyo-sac (Macrospore) OP Pintcs. — 1. The young embryo-sac 

 with its nucleus. 2. The cytoplasm and nucleus have divided to form 

 a tissue the prothallium ("endosperm ") in the sac; x is the cell from 

 which an archegonium will arise. 3. The cell x has had a cell, x^, 

 cut off from it. 4. The cell x^ has divided into cells x., and x^ ; x^ is 

 the rudimentary " body " of the archegonium. 5. The cells a; and ajj 

 are later divided by walls at right angles to the previous ones, and a 

 space arises, the canal, which is lined by the cells so formed. The 

 cytoplasm of ajg usually has a few cells cut off from its upper portion, 

 these being the so-called ventral and neck canal-cells ; the remainder- 

 forms the oosphere. 



