Cavers: Noies on Yorkshire Bryophytes. 243 



small air-chambers, some of which open on the surface by pores 

 situated between the antheridial prominences. These air-pores, 

 thoug-h small, frequently have the cells surrounding- them 

 arranged in tw^o or three tiers, as in the more hig-hly developed 

 barrel-shaped pores of the female receptacle (Fig-. 4, D. ). The 

 antheridia are developed in several long-itudinal rows, the 

 youngest being nearest the anterior margin. Leitgeb"^ states 



Fig. 4.— A.— Longitudinal section of male receptacle; the antheridial cavities are shaded, and 

 the scales and rhizoids on the ventral surface are shown in part. X 20. B. — Transverse 

 section of male receptacle. X20. C. — Horizontal section of a receptacle with two growing- 

 points, the latter showing the youngest antheridia, whilst the oldest occupy the posterior part 

 of the receptacle. X20. D. — Part of A., X 150, showing on the right the upper portion of 

 an antheridium and its cavity, on the left an air-chamber opening by a small barrel-shaped 

 pore ; the cells around the air-chamber contain chloroplasts. 



that the male receptacle of Rehoulia is simply a dorsal out- 

 growth of the thallus, and that the growing-point of the latter 

 does not enter into the formation of the receptacle and can be 

 recognised throughout, lying just below and in front of the 



*Leitg-eb, H., Untersuchungen iiber die Lebermoose, Heft VI., p. 83. 

 J904 Augfust I. 



