ALL FIGURES, UNLESS OTHERWISE STATED, ARE FROM CHARYBDEA.

Fig. 1. This figure represents a transverse section through a portion of the vitreous body of the distal complex eye at about the level x of Fig. 4. Three kinds of areas are seen, namely, the prisms and pyramids with their axial fibers and the distal continuations of the long pigment cells. Towards the lower left of the figure the section is a little more distal than at the right and the transverse areas of the long pigment cells are no more so large as at the right of the figure. The dark granules in the areas of the long pigment cells represent pigment. Camera lucida sketch. ×920. pp. 45, 46, 48, 49, 50, 51, 52, 54.

Fig. 2. This figure is a camera lucida sketch from a section taken transverse through the most distal part of the pigmented zone of a slightly pigmented retina of a distal complex eye. The presence of three kinds of elements is again evident. The dots without the polygonal areas represent the centrad continuations of the axial fibers of the prism cells. The lettering explains the other areas. ×920. pp. 46, 48, 50.

Fig. 3. This is from a section similar to that of Fig. 1, but a little more distal. At the right, the section is more distal than at the left of the figure, in consequence of which the long pigment cells are there taken through their distal fibers. Note the small shrinkage spaces about the axial fibers of the prisms. The white lines bounding the prism areas appear as in nature. The pyramid cells are not shown in this figure. ×950. Camera sketch. pp. 50, 51, 52, 54.

Fig. 4. This figure is from a section taken parallel to the long axis of the cells of the retina of a distal complex eye. It is from a camera sketch, and nothing has been put into the figure except what could be clearly seen. The lateral boundary lines of the prisms are not shown. Note the evidence for the existence of three kinds of cells. ×920. pp. 44-52, 54.

Fig. 5. This figure represents a sagittal section through the nuclear and pigmented zones and the subretinal nerve tissue of a slightly pigmented retina of a distal complex eye, that had been killed in the dark. Camera sketch. The pyramid cells are not shown. ×900. pp. 47, 51, 52, 53.

Fig. 6. These cells are from a preparation by Conant of a sensory club, macerated in acetic acid. Cell a is evidently an iris cell. The others are probably prism cells from the proximal complex eye. ×900. pp. 44, 48.

Fig. 7. In this figure I represent a sagittal section through the distal complex eye. In the middle half of the section, the nuclei, the prism and pyramid cells with their axial fibers, and the long pigment cells with their large distal fibers are all strictly camera lucida sketched. A portion of the pigmented zone has been left unpigmented to better show its structure. At the right and above the concretion cavity is shown a portion of the endoderm of the ampulla. The section is not strictly in a dorsoventral plane of the club, in consequence of which the cells of the ampulla are cut diagonally and through their tips. Note the dumbbell-shaped nuclei of the ampulla cells, as also the masses of secretion. A part of the retina of the proximal complex eye is shown in the upper part of the figure. ×920. pp. 41-54, 63, 64, 68-71.

Fig. 8. These cells are from a macerated preparation. Cells a, b, c, d may be either prism or pyramid cells from the distal complex eye or prism cells from the proximal complex eye. Cells e and f are probably from the right fourth (Fig. 13) of the retina of the proximal complex eye or from the simple eyes. The unlettered cells are probably from the simple eyes. Some of these show a distal process. ×900. pp. 48, 62, 65.

Fig. 9. The cells here figured are long pigment cells from the same preparation as Fig. 6. ×900. pp. 50, 51.

Fig. 10. This drawing shows an end view of a group of prisms from the same preparation as Fig. 6. ×900. pp. 46.

Fig. 11. This group of prisms are from the same preparation as Fig. 6. Two of them are broken off. The fibers seen at the lower end are probably some of the axial fibers. The fiber at the upper end I believe is interprismatic and the distal fiber of a long pigment cell. ×900. pp. 46.

Fig. 12. This figure is a summary of my results on the simple eyes. It is from a camera sketch of one of the distal eyes, but somewhat diagrammatic. The left side of the figure is proximal, the right side distal. ×920. pp. 61, 62, 64, 65.

Fig. 13. Sagittal dorsoventral section of a proximal complex eye. Conant drew and published this as his Fig. 69. Conant’s evidence regarding the axial fibers of the prism cells was incomplete; so that, in this respect, he left his figure unfinished. I have drawn in these fibers and republish the figure. At the right of the retina and next the lens (the white space) the vitreous body is incomplete and the fibers from the retinal cells project freely into the space. This part of the retina also remains unpigmented. Like my Fig. 7, this figure evidently represents a section somewhat to one side of a sagittal dorsoventral plane of the club, so that the endoderm cells of the ampulla are cut diagonally or transversely. pp. 41-44, 60, 64-68.

Fig. 14. This is drawn to show how regularly small shrinkage spaces may occur in transverse sections of the vitreous bodies. This figure is from a transverse section of the vitreous body of a proximal complex eye. I believe that these spaces are determined by the axial fibers of the prisms. Prism outlines are not shown. ×950. pp. 54.

Fig. 15. This figure is a drawing of a portion of a transverse section of one of the simple eyes. Note the flagella from the retinal cells. pp. 62.

Fig. 16. The section of the lower left hand corner of this figure is through a portion of one of the proximal complex eyes, and shows the centrad continuation of the axial nerve fibers of the retinal cells. The section is such, that, besides the simple eye, the nuclei of the proximal complex eye (upper part of figure) and two network cells are cut. ×920. pp. 47, 62, 63.

Fig. 17. A transverse section through the tips of the ampulla cells is here shown. To the left is towards the upper end of the ampulla. The basal bodies with the centrad fibers are in the plane of the section, while the flagella are supposed to extend below the plane of the section. ×1350. pp. 71.

Fig. 18. These bodies, from within the ampulla cells, contain some of the secretion of the ampulla cells, and resemble the “floating bodies.” ×1350. pp. 72.

Fig. 19. The “floating bodies” here represented are from the ampulla. Globules of a secretion similar to that found in the ampulla cells are seen both within and without the bodies. Note also the two black bodies without the cells and two or three similar ones within the cells. These latter bodies are of doubtful nature. ×1320. pp. 72.

Fig. 20. This figure represents sections of the various nuclei found within the ampulla cells. ×1350. pp. 69, 70.

Fig. 21. These cells are from the same preparation as Fig. 6. They are evidently retinal cells from the simple eyes. The tendency of their pigmented ends to become globular, I believe, is due to their having become isolated before they hardened during maceration. ×920. pp. 62.

Fig. 22. This diagram illustrates the retraction of the long pigment cells. The dotted lines in the vitreous body mark the outlines of the prisms, while the continuous lines represent the axial fibers of the prism and pyramid cells. pp. 45, 46, 48, 49, 53.

Fig. 23. These cells are from the epithelium of a sensory club. They are from the same preparation as Fig. 6. Flagella are not shown. ×900. p. 64.

Fig. 24. This group of epithelial cells of a club are from the same preparation as Fig. 6. ×850. p. 64.

Fig. 25. This sketch is a transverse section through the tips of the epithelial cells of a club. The polygonal areas are the cells, while the central dots are the centrad continuations (nerve fibers) the flagella of the cells. ×920. pp. 63, 65, 66.

Fig. 26. The flagella of the epithelium of a club are in this figure seen to extend centrad, some beyond the nuclei. Cell outlines are not shown. ×920. pp. 64, 65, 66.

Fig. 27. The cells of the lower half of this figure belong to the ampulla, those of the upper half to the canal of the peduncle. The right side of the figure is towards the eyes (the ventral side) of the club. Globules of secretion are seen within the ampulla cells, as also a globule without. The ring above the latter globule is probably an empty shell of a floating cell. ×1320. pp. 68, 69, 71, 73.

Fig. 28. This figure is from a transverse section of a tentacle of Charybdea. The mass with darkly stained granules is the remains of a thread cell. The ectoderm and a small part of the supporting lamella only are figured. Note the large ganglion cell. ×920. pp. 74, 75.

Fig. 29. Part of a transverse section of a tentacle of Tripedalia. The endoderm is not figured. The supporting lamella is seen to be considerably thinner than in Charybdea. Note the subectodermal muscles, as also the muscle fibers to the thread cells. ×920. pp. 69, 74, 75.

Fig. 30. This is a transverse section through the endothelium of a tentacle of Charybdea in the line c d of Fig. 32. The dark lines bounding the polygonal areas are the thickenings of the sides of the walls of the cells in the line indicated. The central dots are the centrad continuations of the flagella. ×920. p. 76.

Fig. 31. This figure is a transverse section through a tentacle of Charybdea at about the middle of Fig. 32, i. e. so near to where the tentacle joins the pedalium, that the muscles within the lamella have all come to lie under the ectoderm. The ectoderm is not shown. ×920. pp. 75, 76.

Fig. 32. A longitudinal section through the supporting lamella only, of a tentacle of Charybdea, is here shown. In the upper part of the figure the muscle fibers are seen wholly enclosed by the supporting lamella. In the middle of the figure they are seen to pass out of their canal. In the lower part of the figure, the supporting lamella is seen to bend to the right where it becomes continuous with the lamella of the pedalium. ×920. p. 75.

CUBOMEDUSÆ. PLATE I.

E. W. Berger, del.