. Cephalopoda. Cephalopoda. Behind the eye there is a round, flat papilla, the "olfactory organ" (see p. 82). (96) (96). FIGURE 27. Diagrammatic frontal sections of the development of the right eye of Cephalopoda: a — Nautilus. The stalk bears the optic nerve (n); the retina (ret) is actually many-layered with the rods pointed toward the light; other elements are the primary pupil (pp) and the ring fold (ir) which forms a wide circle and probably corresponds to the iris of Dibranchiata; b — e — typical stages of the embryonic eye of Sepia. The eye chamber is completely closed. The do
. Cephalopoda. Cephalopoda. Behind the eye there is a round, flat papilla, the "olfactory organ" (see p. 82). (96) (96). FIGURE 27. Diagrammatic frontal sections of the development of the right eye of Cephalopoda: a — Nautilus. The stalk bears the optic nerve (n); the retina (ret) is actually many-layered with the rods pointed toward the light; other elements are the primary pupil (pp) and the ring fold (ir) which forms a wide circle and probably corresponds to the iris of Dibranchiata; b — e — typical stages of the embryonic eye of Sepia. The eye chamber is completely closed. The double epithelial lamella (pc), which becomes thinner later, forms the lens (1) at the site of the primary pupil; only the inner segment of the lens is formed at first. (Compare description of development in Volume II.) Close around the lens develops the iris fold (ir). The resulting eyeball (e) is comparable to that of Nautilus in the following aspects: it projects from the head, and is borne in the embryo on a more or less distinct stalk which is much thicker here because the organs it contains are more developed than those of Nautilus (optic ganglion, white body; see Figure 28).. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Naef, Adolf. Jerusalem : Israel Program for Scientific Translations
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Keywords: ., bookcentury1900, bookcollectionbiodivers, booksubjectcephalopoda
