EMBEYOGENT IN HEPATIC^. 



275 



The archegonia of Hepaticse are either situated in the substance 

 of the thallus, as in Eiccia and Anthoceros, or they are raised upon 



Pig. 488. 



stalks, as in Marchantia (fig. 491) and Jungermannise. In Mar- 

 chantia these stalks bear radiated receptacles, r, on the under surface 

 of which the sporangia are placed, which are peculiar bottle-shaped 

 bodies (fig^ 492) containing germ-cells. 



The spermatozoids enter the archegonia, and thus a cell is fertilised, 

 from which the sporangium or spore-capsule, a distinct body, is pro- 

 duced (fig. 491 s), constituting the second generation. In Junger- 

 mannia bicuspidata (fig. 493) there is represented at a an arche- 

 gonium containing an unimpregnated germ-cell, and at 5 an arche- 

 gonium containing an impregnated germ-cell, which is the rudiment- 

 ary spore-capsule. The germ-cell, after fertilisation, shows two 

 nucleated cells, c, and from it, as a second generation, the fruit- 

 Fig. 488. A species of Liverwort (JlfarcAaw(m poZywiorpfea), with its green thaUus, t, bearing 

 a cup-like body, g, in which minute cells or free buds (sporules of some) are seeli, and a 

 stalked receptacle, s r. In the substance of the disk -like receptacle, r, cells are produced con- 

 taining spermatozoids. These are considered antheridia. Fig. 489. Vertical section of the 

 disk-like receptacle of Liverwort (Ma/roha/ntia), showing the antheridia, a a, in its substance. 

 These antheridia are flask-shaped sacs containing phytozoary cells. They communicate 

 with the upper surface, and their contents are discharged through It. Between the anther- 

 idia there are air cavities, e c, connected with stomata, s s. 



