240 



Evans: Air chambers of Grimaldia fragrans 



section, cut immediately below the epidermis, and seems at first 

 to belie his statement. The figure shows the partitions, almost 

 complete, of an air chamber, the cells being distinguished by stip- 

 pling. Only one end of the chamber is represented ; the other end 

 did not show because the section was slightly oblique in that 

 region and passed through the epidermis instead of the green 

 tissue beneath. That the stippled cells represent the boundaries 

 of a chamber is evident from their close union and also from the 



Fig. 3. Section parallel with the surface, just below epidermis, X 270. 

 Fig. 4. Section a short distance below the one shown in Fig. 3, X 270. 



fact that an epidermal pore was situated above the middle of the 

 space which they enclose. It will be seen that the chamber con- 

 tains a number of cells, circular in section and either entirely free 

 or else loosely connected with one another or with the cells of the 

 partitions. Similar cells are shown elsewhere in the figure, and a 

 superficial examination would interpret them as the sections of 

 filaments, especially if they were considered in connection with 

 Fig. I. 



The incorrectness of this interpretation is brought out by a 

 comparison with FiG. 4, which shows the same chamber at a 

 lower level, the cells of the partitions being again indicated by 

 stippling. In this figure the complete boundaries of the chamber 



