Hollowat. — Prothallus, &c, of Tmesipteris. 



413 



is given in figs. 70a to 70f. The section marked A passes through the apical 

 cell of the shoot, and shows that it segments regularly from four sides. 

 B, C, and D show the differentiation of the strand in progressively older 

 regions of the shoot. Section E is taken at a point a little above the main 

 basal wall, and shows the narrow conducting-elements which lead down 



Fig. 71. — -The apex of a young prothallial plantlet in longitudinal section, 

 showing the apical cell and its segmentation. X 75. 



Fig. 72. — The point of attachment of a young plantlet to the prothallus, 

 showing unusually long intraprothallial shoot-region. The extra- 

 prothallial shoot-region is cut obliquely. X 80. 



to it from the shoot. Section F shows the foot in transverse section a 

 little below the basal wall, the original first inclined wall in the hypobasal 

 region of the embryo being still very evident. The haustorial outgrowths 

 from the foot of a well-grown plantlet are illustrated in my previous paper 

 at Plates II and III and figs. 58 and 59, the main basal wall appearing in 

 the latter figure. In fig. 72 in the present paper is shown a young plantlet 



