Note f — HISTOLOGICAL.

I go into this at some length because the cell-walls in the series that showed the nuclei best differentiated as lighter and darker ones did not show well, and there might be some doubt that these lighter nuclei belonged to the pyramid cells. I could, however, in many instances, trace the axial fibers of the pyramids through the pigmented zone to these lighter nuclei (as already noted) which fact can leave no doubt but that some of these nuclei belong to the pyramid cells. (Similar nuclei, however, are found to belong to the long pigment cells, to be described below.) Centrad these pyramid cells are continued into a single process just as the prism cells were shown to be (Fig. 7). Figures 6, 8, 9, and 21 show samples of all the pigmented cells found in macerated preparations, and none of these (except Fig. 9, long pigment cells) show more than a single centrad process. Hence, I conclude that centrad both the pyramid cells and prism cells are continued as a single prolongation.