426 
Lang. — On the Morphology of Cyathodium. 
Fig. 28. Anterior margin of a branch of the thallus seen from below, showing an antheridio- 
phore and two involucres. The involucre to the left encloses a mature sporogonium, while that to 
the right bears only unfertilized archegonia. x 25. 
Fig. 29. Antheridiophore in vertical section ; the lower antheridia are mature, x 375. 
Fig. 30. Younger antheridiophore, showing the septa between the antheridia. x 375. 
Fig. 31. Young antheridiophore in surface view, x 670. 
Fig. 32. Young antheridiophore, which can clearly be traced back to three marginal cells, in 
surface view, x 670. 
Fig. 33. Vertical section of a young antheridiophore similar to that in Fig. 32. x 670. 
Fig. 34. Median section through an apex which has produced the first archegonium. x 375. 
Fig. 35. Median longitudinal section through an older apex, which has formed a group of 
archegonia, showing the construction of the involucre in this species. This figure is based on two 
adjoining sections and is slightly diagrammatic, x 200. 
Fig. 36. Transverse section across an involucre of the same age as that in Fig. 35. x 200. 
Fig. 37* Involucre bearing an advanced sporogonium seen from below to show the presence of 
rhizoids and ventral scales upon it. x 64. 
Fig. 38. Embryo consisting of three cells enclosed in the archegonium. x 375. 
Fig. 39. Older embryo, showing the four segments ; vertical walls have been formed in the 
upper two. The venter of the archegonium has become several cells thick, x 375. 
Figs. 40, 41. Young sporogonia in which the regions derived from the four first segments of the 
embryo can be recognized, x 375. 
Fig. 42. Transverse section through the lower tier of the upper half of a sporogonium about 
the age of those in the preceding figure, x 375. 
Fig* 43- Longitudinal section through the upper part of the capsule of a somewhat older sporo- 
gonium, showing the origin of the lower layer of cells of the apical disk, x 375. 
Fig. 44. Longitudinal section of an almost mature sporogonium. x 200. 
Fig. 45. The apical disk of the same sporogonium in median section, x 200. 
Fig. 46. Foot of a similar sporogonium, showing the processes produced from the large basal 
cells, x 200. 
Fig. 47. Cells of the lower part of the wall of the capsule in surface view. X 530. 
Figs. 48, 49. Longitudinal sections through sporogonia of C. foetidissimum (Fig. 48) and 
C. cavernarum (Fig. 49) to show their position on the thallus and their relative size. In both cases 
the sporogonia contained spores and elaters with their walls thickened, but had not quite attained 
the full size, x 74. 
