Holloway. — The Prothallus and Young Plant of Tmesipteris. 17 



nuclei and the deeper staining both of these and of their other cell-contents 

 than is the case in the ordinary vegetative cells. They do not arise so 

 near the actual apex of the prothallus as is the case in the Ophioglossaceae 

 or as I have found in the epiphytic prothalli of Lycopodium Billardieri. 



Figs. 22-33. — Series showing the development of the antheridium. X 150. 

 Fig. 34. — Mature antheridium, showing opercular cell. X 137. 



In the development of an antheridium from an epidermal cell the 

 first division wall to be formed is a periclinal one cutting off an outer 

 from an inner cell (figs. 22 to 25). Sometimes the inner of these, and at 



