E. W. BERGER ON THE CUBOMEDUS^. 53 



dark, but just how this is accomplished whether the whole cell with 

 its nucleus takes up a deeper position, the cell substance at the same 

 time collecting in the region about the nucleus, as shown in Fig. 5 

 and the diagram (Fig. 22), I cannot with certainty state. It would 

 seem, too, as though the pigment became less in the cells exposed to 

 darkness, for I rarely, even in the most retracted heavily pigmented 

 series, saw the pigment to extend farther towards the nucleus than 

 commonly. The time of keeping in the dark, prior to fixing, varied 

 from three-fourths of an hour to one and one-half hours. I could 

 not bring the amount of retraction into relation with the time of 

 exposure, except that in general the retinas longest exposed showed 

 the greater amount of retraction. 



(d) The tissue underlying the retina is described by former 

 observers (Glaus, Schewiakoff, Conant) as composed of nerve-fibers 

 and ganglion cells. I cannot give it any other interpretation, but I 

 must add that the supposed ganglion cells are seen only as nuclei, 

 no cell bodies ever being demonstrable in any of my sections. Conant 

 also recognized no cell bodies. Occasionally, as in Fig. 7, long fibers 

 could be traced for some distance in this subretinal tissue, in some 

 instances quite to or from a visual cell. Pigment was not regularly 

 observed in this tissue, as Schewiakoff describes, and when present I 

 believe it has been dissolved in from the pigmented zone. 



(e) Schewiakoff describes the retina (my pigmented and nuclear 

 regions) as composed of spindle-shaped visual cells (my pyramid 

 cells?) alternating with pigmented supporting cells (long pigment 

 cells), with the nuclei of the former lying more centrad than those of 

 the latter. The visual cells are pigmented only at their periphery, or 

 surface, leaving an unpigmented axis, while the supporting cells have 

 pigment throughout their whole substance within the pigmented 

 zone. Distally, the visual cells have hyaline rods, or fibers, which 

 extend into spaces in the vitreous body, and pass through this and 

 the capsule to the lens. The vitreous body is described as homogene- 

 ous, except the spaces for the visual rods, and a secretion from the 

 retinal cells. 



It will thus be seen that my results are quite different from 

 those just described. I find the vitreous body to be composed of 

 prisms and pyramids with axial fibers, while the long pigment 

 cells (supporting cells of Schewiakoff) are continued into the 

 vitreous body, and becoming narrowed into a non-pigmented fiber, 



