G. S. West and Olive E. Hood , 
244 
Injury or removal of this cap appears to be followed by the 
rapid formation of another one. 
The apical cap differs from the cell-wall in structure and in its 
behaviour when treated with various reagents and stains. The caps 
are insoluble in an ammoniacal solution of cupric hydrate, although 
they may swell considerably, and they are very slowly soluble in 
Fig. 3. Three apical cells of T. Montis-Tabides var. ceylattiici showing the 
apical caps. In C there are two caps both of which have come loose on 
treatment with chloral hydrate, x 800. 
sulphuric acid. They are not coloured with sulphuric acid and 
iodine, neither are they stained with chlor-zinc-iodine. These 
negative reactions indicate that the caps are either chitinous or 
pectic in character. Further tests showed no staining with picro- 
carmine or picric acid and borax-carmine, nor any yellow colouration 
with picric acid or picro-sulphuric acid. Moreover, they are easily 
soluble in a 2% solution of potash, and therefore the caps do not 
contain chitin. They stain deeply, however, with methylene blue, 
Fig. 4. Three apical cells showing a series of apical caps. In C the 
serrated fringe of a loose cap is well shown, x 800, 
