68 HOEMEISTER, ON 



and of Fmllania are remarkably distended at the place 

 where the large cell at the base of the neck is enclosed ; 

 those of Fmllania have a longer neck than any moss or 

 liverwort, without exception, with which I am acquainted 

 (PI. XII, figs. 1, 3). 



With a few exceptions peculiar to the Jungermanniae 

 proper (PI. VII, fig. 15; PL VIII, fig. 2 ; PL X, fig. 1), 

 the archegonia of the leafy liverworts agree in the fact that 

 until the formation of the rudiments of the fruit, the mother- 

 cell of the large cell at the apex of the distended portion, 

 is enclosed only by a single layer of cells ; and they also 

 agree in the fact that the distended portion is only of 

 moderate height, and that before impregnation only two or 

 three, or at the most four cells, are to be counted between 

 the lower arched surface of the above-mentioned large cell 

 and the base of the archegonium. 



The archegonia of the greater number of leafy liverworts 

 are furnished with a peculiar cup or pitcher-shaped organ 

 of later growth than the archegonium itself — the calyx or 

 periantltium of authors. In all cases which have been 

 observed, the first appearance of this organ is in the form 

 of a closed ring, consisting of a single layer of cells. 



This is the case in the very different perianths of 

 Fmllania and Kadula, and of Jungermannia bicaspidata 

 and divaricata. The first rudiment of the perianth is 

 formed by a contemporaneous protrusion, outwards and 

 upwards, of a belt of cells belonging to the apex of the 

 stem, surrounding the archegonia ; and by the separation of 

 the protruding portion of the cells, from the portion lying 

 within the body of the stem, by means of a transverse 

 septum. The like form of division is repeated several 

 times in the coronet of apical cells of the young organ. In 

 Badula complanata it lasts until the perianth has completed 

 the full number of its cells in the direction of its length. 

 Here and there cells belonging to the margin are also at 

 the same time divided by vertical septa, and thus the 

 number of cells of the circumference is increased above 

 (PL XI, fig. 1). The form of the perfect perianth of 

 Radula is consequently that of a horn ■ continually 

 widening upwards, and closely compressed laterally ; doubt-' 



