staining. (Pip;. 12). 



Of the foui' layors in the pollen sac wall only 

 the subepidermal layer has any part in the opening of 

 the anther. This layer is made into the fibroizs lay- 

 er. It covers th'3 whole introrse face of the anther, 

 and over the v/hole surface of the pollen sacs. The 

 first, and for a long time the only evidence of the 

 formation of this layer is the radial lengthening of 

 the cells. At i.his stage it is possibly not inappro- 

 priate to digress for a single instance of regenera- 

 tion observed in this fibrous layer. From some un- 

 known cause, the first subepidermal layer had been de- 

 stro2''ed over a small area. The; i'emaining part of that 

 layer had developed normally. Into this gap tissue 

 had grown from both sides, but that which came from 

 below was slight in amoiint , and had retained its orig- 

 inal character. YP.iile the epidermal cells had great- 

 ly elongated and had cut off short secondary epidenn- 



