E. W. BERGER ON THE CUBOMEDUS^. 47 



fiber. I believe this to be so because the fiber is evidently sensory, 

 and a priori we should expect it to be so continued. Further, I 

 find decided evidence in sections of the simple eyes to show that the 

 fibers there extend past the nucleus into the subretinal tissue where 

 I could not trace them farther. (Fig. 16.) Again, that the flagella 

 of the epithelial cells of the club are also continued into the cells, 

 in some instances could be traced past the nuclei (Figs. 12 and 26), 

 and the fact, too, that the retinal cups of the eyes represent 

 invaginated epithelium (the axial fibers of the prisms are hence 

 cilia?) all this leads me to believe that the axial fibers of the prism- 

 cells extend centrad past the nuclei through their cells and are 

 continued as nerve-fibers. (See below under pyramid-cells and under 

 epithelium). Immediately upon entering the pigmented part of its 

 cell the axial fiber of a prism-cell has a dumbbell-shaped enlarge- 

 ment which lies quite at the distal edge of the pigmented part 

 of the cell (Fig. 7, uiipigmented part of figure). This, of course, can 

 be seen only in unpigrnented retinas. This dumbbell-shaped body, 

 (Basalkorperchen of Apathy), which name I give it, since it evidently 

 is homologous to the basal bodies described by others for the cilia of 

 epithelia, can be most beautifully seen as two minute spheres lying 

 close together and in line with the nucleus. These two little spheres 

 of the basal bodies put to the test the highest powers of the 

 microscope; but, when, after a prolonged and careful study, one 

 satisfies himself of their existence and exact shape, the very difficulty 

 with which they are resolved adds a zest to be appreciated. The 

 length of a basal body is about one-fifth to one-fourth that of the 

 nuclei of the prism-cells. 



The structure of the nuclei of the prism-cells is that of a dense 

 network (Figs. 4, 7, npr) which stains dark with heematoxylin. A 

 nucleolus can often be seen in these nuclei. In some few series, 

 again, these nuclei did not show a network-like structure, but the 

 chromatin was arranged in masses (Figs. 5, npr). These nuclei can 

 usually be distinguished from those of the other cells of the retina 

 by their denser, darker-staining network (Figs. 4, 7, npr), or as 

 shown in Fig. 5 (npr). Their denser structure and staining capacity 

 are a distinguishing characteristic of the nuclei of the prism-cells. 

 I must add, however, that not in every series is this apparent. 



That portion of a prism-cell that contains the nucleus rarely 

 contains any pigment; and when pigment is present, I believe that 



