FTTNARIA. 333 



the calyptra from the upper end of the young rod-like 

 sporogonium, then pull the lower end of the latter out of 

 the stem tissue. If the upper end of the sporogonium 

 breaks off and is left behind in the narrow upper portion 

 of the calyptra, try again until you get the sporogonium 

 isolated without damage. Note that the upper portion is 

 green, while the sharply pointed lower end is colourless or 

 reddish. Examine the upper end with the high power; in 

 surface view the cells are seen to -be arranged in regular 

 transverse rows ; focus carefully, and note the well-defined 

 apical cell, from which segments are cut off by walls 

 parallel to its two sloping sides, and the very regular 

 arrangement of the tissues for some distance below the 

 apical cell. 



Remove the calyptra from successively older sporogonia, 

 and note that at a relatively late stage the sporogonium 

 shows differentiation into capsule and seta, in the form of 

 a thickened zone between the two this thickening forms 

 the apophysis, at first thicker than the capsule itself. 

 Before this, however, the enlarged lower portion of the 

 calyptra ceases to keep pace with the elongating sporo- 

 gonium, and is ruptured by a circular rent near the base, 

 the upper part being carried up as a pointed cap on top of 

 the sporogonium. 



474. Operculum, Peristome, Annulus (Figs. 78-82). 

 In nearly ripe capsules, note that the convex lid or 

 operculum which covers the apex is oblique sometimes 

 nearly parallel to the long axis of the capsule. 



(a) Remove the operculum, and note that its outer layer 

 consists of thick- walled cells running in spiral lines from 

 the rim. to the raised central point. The removal of the 

 operculum brings to view the sixteen curved teeth of the 

 outer peristome. With a razor, cut off the peristomes 

 of several capsules, mount some with the upper surface 

 uppermost, others with the lower surface uppermost. 



(6) Note that the peristome consists of two series of 

 curved narrow triangular plates or teeth, sixteen teeth in 

 each series ; the teeth of the outer peristome are directly 



