n 



MUSCINE^—HEPA TIC X— MARCH AN TI ALES 



6i 



(i, 2) and others in Marchantia, Grimaldia, and Preissia, and 

 probably occurs normally in all Marchantiacese. 



After the first anticlinal walls are formed in the octants, no 



Fig. 23. — Targionia hypophylla. A, Longitudinal section of the venter of a ripe 

 archegonium, X500; B-E, development of the embryo, seen in longitudinal 

 median section — B, two-celled, D, four-celled stages, X500 except E, which is 

 magnified 150 times; F, median section of the upper part of an older embryo, 

 X250. 



definite order could be observed in the succeeding cell divisions, 

 especially in the lower half of the embryo. In the upper part 



