Holloway. — Prothallus, &c, of Tmesipteris. 



397 



inclined wall is alone present (figs. 41a to 41c). The section marked D 

 probably also represents the embryo in section below the basal wall, 

 showing a wall in each of the hypobasal quadrants which has led off from 



Figs. 35a-3.5d, 36a-36d. — -Two young embryos in longitudinal section, shoeing basal 



wall and also first hypobasal wall. X 100. 

 Figs. 37a-37f. — A young embryo in transverse section from below upwards, showing 



first hypobasal wall. X 100. 

 Figs. 38a, 38b, 39a-39d. — Two young embryos in longitudinal section, showing^basal 



wall and also first epibasal and hypobasal walls. X 100. 



the first inclined wall. In the epibasal region also (figs. 41e, 41f) the 

 segmentation is not octant-wise. Figs. 42a and 42p» show a slightly older 

 embryo in longitudinal section, in which a regular segmentation of the 



