EXPLANATION OF THE PLATES.

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PLATE III.

Figs. 1—8. Achltja prolifer a Nees.

Clavate expanded extremities of the branches.

1. Part of the contents form an elliptical accumulation,which loses itself pretty gradually, externally, in theremainder of the cell-contents, and from which radiatingthreads of circulation proceed.

2. The elliptical accumulation presents a better de-fined outline ; there are still some few threads of circula-tion.

3. The agglomerated portion of contents has becomeconverted into a cell (sporangium) by the formation of amembrane. This is densely filled with granular mucilage.

4. The sporangium-cell is filled with dark, granularcontents, and inclosed by a tolerably thick membrane.It has grown out, upward, and downward, into two pro-cesses (branches). These have a delicate membrane andcontents, consisting of mucilage, homogeneous towards thesummit at least. They elongate by apical growth.

5. Three free sporangial cells have been formed in theend of a branch. They contain homogeneous mucilage.

6. Two free sporangial cells, each of which has grownout into a process. One sporangium is densely filled withminute cellules. The other has already discharged thegreater part of the motile cellules through the opening ofthe apex of the process.

7. The entire end of the branch has become a spo-rangium, the whole of the contents having become isolatedand converted into a cell by parietal cell-formation. Thisis filled with granular mucilage.

8. As in fig. 7. The sporangium has grown out atthe apex into a short process. It is crowded with minutecellules.