IV. THE ANTHOCEROTES I3S 



first division wall is parallel with the axis of the archegonium 

 and divides the embryo into two equal parts, in which the 

 character of the cells remains much as in the undivided tgg. 

 Here too the granules are most abundant about the nucleus, 

 from which radiate plates that separate the vacuoles. The 

 next divisions are transverse and divide the embryo into two 

 upper large cells and two lower smaller ones. The embryo at 

 this stage is oval and more or less pointed above. In each of 

 the four primary cells vertical walls arise that divide the 

 embryo into octants, but the upper octants are decidedly larger 

 than the lower. Next, in the upper cells, transverse w^alls are 

 formed and the embryo then consists of three tiers of four cells 

 each. Of these the cells of the upper tier are decidedly the 

 larger. At this stage, in neither species examined by me, 

 were any traces present of the projection of the basal cells 

 figured by Leitgeb (1. c. PL L). As his drawings w^ere made 

 from embryos that had been freed from the thallus, probably 

 with the aid of caustic potash, it is quite possible that this ap- 

 pearance was due in part at least to the swelling of the cell 

 walls through the action of the potash. At any rate in micro- 

 tome sections of both species in these early stages, the basal 

 cells do not project in the least (Fig. 70, A). The next di- 

 visions are very uniform in the upper tier of cells, from which 

 the capsule develops, but less so for the two lower ones. In 

 the upper tier, seen in cross-section (Fig. 70, B i), a slightly 

 curved wall running from the median wall to the periphery 

 forms in each quadrant, which thus viewed is divided into an 

 inner four-sided and outer three-sided cell. In the former a 

 periclinal wall next forms, w^hich cuts off an inner square cell 

 (Fig. 70, D). In longitudinal section these periclinal walls 

 are seen to be concentric with the outer walls of the cells, and 

 to strike the median and quadrant w^alls at some distance below 

 the apex of the sporogonium so as to completely enclose the 

 central cells (Fig. 70, C). By the formation of these first 

 periclinal w^alls the separation of the columella from the wall 

 of the capsule is completed, and this is not unlike w-hat obtains 

 in the sporogonium of many other Hepaticse; but an essential 

 difference must be observed. In the latter the central group 

 of cells forms the archesporium ; here these cells, as we shall 

 see, take no part in spore formation. In the lower tiers of 

 cells similar but less regular divisions occur (Fig. 70, D 2), 



