14 INTRODUCTION. 



actually dissolved, or is extremely transparent. In 

 most cases the spiral is double, but rarely single, a 

 portion of them fall away with the spores, whilst 

 others remain attached to the valves. The old 

 notion that their function was to aid in the disper- 

 sion of the spores does not seem to be supported by 

 evidence. "In some genera a few of the apical 

 elaters, and in others a few of the basal ones, persist 

 for some time after the bursting of the capsule, and 

 retain a good many of the free elaters entangled in 

 them, but finally fall away. These elater-holders, 

 as they have been called, are usually (but not always) 

 shorter and wider than the free elaters, and do not 

 generally agree with them in the number of included 

 spirals." In Anthoceros the elaters are transverse 

 rows of cells without spiral bands. The structure 

 and development of the elaters in Marchantia were 

 investigated by Professor Henfrey and made the 

 subject of an elaborate memoir. 



The male inflorescence consists of antheridia 

 which are developed in various ways. The antheri- 

 dium itself consists of a globose, or ellipsoid, body 

 surmounting a rather short pedicel. In the foliose 

 Jungermanniece they generally occupy the axils of 

 leaves, either singly or in groups. The body of 

 the antheridium encloses within it the mother 

 cells of the antherozoids, which escape on the 

 access of water, and then separate, the antherozoids 

 becoming free. The free antherozoids resemble 

 curved threads, wound spirally from one to three 

 times, provided at one end with a pair of long and 



