Ill 



THE JUNGERMANNIALES 



81 



antheridium body (Fig. 33, D). At this stage and the one 

 preceding it Sphcerocarpus recalls the structure of the anther- 

 idium of the Characeae, although the succession of walls is 

 not exactly the same. The divisions of the central cells are ex- 

 tremely regular, walls being formed at right angles, so that 

 the sperm cells are almost perfectly cubical, and the limits of 

 the primary central cells are recognisable for a long time. 



The development of the antheridial envelope begins much 

 earlier than that about the archegonium, but in exactly the 

 same way. By the time that the wall of the antheridium is 

 formed the envelope has already grown up above its summit, 

 and as the antheridium develops it extends far beyond it like 

 a flask, at the bottom of which the antheridium is placed, and 

 through whose neck the spermatozoids escape. These are 



A B E 



FIG. 33. Sphccrocarpus sp (?). Development of the antheridium. A-D, Median lon- 

 gitudinal sections, X4So; E, an older one, X225; F, a spermatozoid, killed with 

 osmic acid, Xpoo. 



very much like those of the other Hepaticae, and in size exceed 

 those of most of the Marchantiaceae, but are smaller than is 

 usual among the Jungermanniales. 



Leitgeb studied the germination of the spores in 3\ terres- 

 tris, which remain permanently united in tetrads. He found 

 that all the spores of a tetrad were capable of normal develop- 

 ment, which does not differ from that of Riccia or other thal- 

 lose Liverworts. A more or less conspicuous germ tube is 

 found at the end of which the young plant develops, one of the 

 octants of the original terminal group of cells becoming, appar- 

 ently, the apical cell for the young plant. The latter rapidly 



grows in breadth and soon assumes all the characters of the 

 6 



