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bursts, and from it is given off a clond of fine particles, which are the sper- 

 matozoids, coiled up and swarming about. These have been observed to 

 pass down to the central cell, where they are absorbed. 



No sooner has the central cell become impregnated than the upper part 

 withers and the large central cell begins to grow and develop. As it grows 

 it pushes off and breaks away the covering skin. It does not begin to 

 enlarge until it has continued growing some time, and then, the seta having 

 attained its full height, begins to expand. This at the top forms the 

 calyptra and capsule, the little sheath at the bottom is called the vaginula, 

 the leaves round it are termed the perichsetium. 



The seta having attained its growth, the capsule begins to enlarge, the 

 calyptra expands, resting on the top of the lid, and taking various shapes 

 according to the way the capsule stretches it. In some cases it is simply 

 split up. Sometimes it is of a conical form, and splits up because there is 

 no room for the capsule within it, as in the Funaria ; in Encalypta it comes 

 off as a small cone or extinguisher. 



The calyptra being thrown off the capsule is seen in its natural condition, 

 closed in most cases by a lid or operculum, sometimes of a conical shape 

 sometimes with a very long beak. In a few cases, as in Phascum, the 

 capsule is always globular, and a mass of spores escapes through an opening 

 caused by the rotting of the plant. Sometimes the capsule drops off the 

 stalk, leaving a little hole at the bottom through which the spores escape. 



The lid of the capsule falling off, there appears the beautiful appendage, 

 which has been termed the peristome, with a number of teeth, commonly 

 sixteen, standing up or spreading out in various directions. This is termed 

 a single or double peristome according as it has one or two rows of teeth. 

 In some cases the interior is membranous. He preferred to call the interior 

 row the endostome, within the mouth, for this reason ; if a vertical section 

 be made of the capsule of Mnium it will be found that the outer row of 

 teeth of the peristome springs from the inner wall of the capsule, but where 

 there is a second row, that springs from the wall of the spore sac. He also 

 noticed another part of the interior of the spore sac, namely the columella or 

 central pillar, from which the operculum or lid has been thrown off. In 

 some cases it runs up to the top of the peristome, and expands into a mem. 

 brane, closing the mouth of the capsule. 



In the beautiful family of the Polytricliums this columella takes various 

 forms. In some cases it has wings, in others the spore sac is attached to 

 the wall with jointed threads, which act as ropes or stays. 



There are two modifications of the peristome, as already mentioned. 



In cases where the mouth of the capsule is naked, as in the gymnostomous 

 mosses, by the plan formerly adopted these mosses are separated from 

 genera to which they are otherwise closely allied ; but in very many cases it 

 is not possible to see the peristome or even the fruit, yet by the leaves and 

 habit of the plant they can be placed with mosses which have a peristome, 

 and to which they are otherwise perfectly related. In all these cases the 

 spores are contained in a bag or spore sac, and when the lid comes off the 

 spores pour out. These organs are most distinct and easily examined. 



