EK. W. BERGER ON THE CUBOMEDUSA. 49 
which fact is characteristic. In the axis of each pyramid is a 
darkly-staining fiber quite like the one described for the prism- 
cells (Figs. 1, 4, 7, 22). That this fiber extends distally beyond the 
limits of the pyramids I could not determine, but I do not think 
that it does. Centrad this fiber extends into the pigmented portion 
of its cell quite to or near the nucleus as was described for the 
fibers of the prism-cells (Figs. 7, 22). Whether or not these fibers 
extend past the nucleus and become continued as nerve fibers, the 
same course of reasoning holds as was given for the fibers of the 
prism-cells. Each of these fibers possesses a basal body just on its 
entrance into the pigmented part of the cell (Fig. 7), but I could 
not determine that it was dumbbell-shape. In form it represents 
an enlargement of the fiber itself, which gradually tapers again to 
its normal size. The continuations of these fibers within the pig- 
mented parts of the pyramid-cells, as also the basal bodies, could 
only be demonstrated in unpigmented series. 
Patten’ describes axial fibers extending centrad through the rods 
(vitreous portions) of retinal cells (“retinophora”) into the region 
of the nucleus and past the nucleus (arthropods and molluscs). My 
retinal cells (prism and pyramid cells) evidently correspond to Patten’s 
retinophora, but I find no evidence that one of my retinal cells 
represents more than a single cell, while Patten gives evidence that 
his retinophora are made up of two cells closely applied to each other 
as twin cells. If this were also true for the retinal cells that I have 
described, I believe my macerated preparations would have shown 
it. Schreiner’? and Hesse’ also figure and describe axial fibers for 
the rods of the visual cells in polychetous annelids, and Schreiner!* 
also for molluscs. Neither of these observers finds the fibers to extend 
distally beyond the rods nor centrad toward the nucleus as Patten 
and myself show. Neither Schreiner nor Hesse figures these cells as 
twin cells as Patten does, so that to my knowing Patten stands 
alone in this respect. Andrews" describes and figures rods for the 
visual cells of polychaete annelids but no axial fibers. He was the 
first to describe these rods in annelids. 
The pigmented zone of the pyramid cells, in heavily pigmented 
series, is filled throughout with dark-brown pigment granules, and is 
quite like that of the prism cells (Figs. 4, 7). In transverse sections, 
however, through the most distal part of the pigmented zone, of 
unpigmented series (Fig. 2), lighter areas with central dots could 
5 
