Fig. 52. Similar section to last, but nearer to perradius, to show sub-endodermal tract of nerve fibres.
Fig. 53. Sensory organ in proboscis of Tripedalia, as seen from surface in living animal.
Figs. 54 and 55. Sections of same sensory organ.
Fig. 56. Vertical section through one side of proboscis, to show sensory organ attached to endoderm. (Tripedalia.)
Fig. 57. Diagram of the outlines of sensory club seen from the side, by camera lucida.
Fig. 58. Part of retina of larger complex eye cut radially.
Figs. 59-62. Four sections in direct sequence through retinal cells transversely, larger eye.
Fig. 63. Transverse section through the tips of cells of a slightly pigmented retina, larger eye.
Figs. 64-66. Three transverse sections through vitreous body at different levels. All from same series, but not in direct sequence; larger eye.
Fig. 67. Radial section through retina, to show fibres from the long pigment cells; larger eye.