. Cephalopoda. Cephalopoda. FIGURE 8. Three young stages of Nautilus (hypothetical) (natural size). They are the nucleus of older shells of 3 stages of growth; the soft parts of the young animal or embryo are only indicated. A freshly-hatched Nauti- lus has 7 chambers, the 8th chamber being much smaller than the preceding ones, as in young Sepia (). The successive stages have one, two, and three chambers. At the latest after completion of the third chamber, the dorsal margin of the shell must reach the site of the assumed embryonic chamber (indicated by dotted line), which must be removed
. Cephalopoda. Cephalopoda. FIGURE 8. Three young stages of Nautilus (hypothetical) (natural size). They are the nucleus of older shells of 3 stages of growth; the soft parts of the young animal or embryo are only indicated. A freshly-hatched Nauti- lus has 7 chambers, the 8th chamber being much smaller than the preceding ones, as in young Sepia (). The successive stages have one, two, and three chambers. At the latest after completion of the third chamber, the dorsal margin of the shell must reach the site of the assumed embryonic chamber (indicated by dotted line), which must be removed to permit the second coil to be attached to the first. The first coil is evolute, of Cyrto- ceras type, the second coil is attached tangentially to the first, and the next coils show an increasingly involute nature: 1 — hypothetical embryonic chamber; 2 — first air chamber; 3 — second air chamber; 4 — third air chamber; 5 — living chamber; 6 — central hole through Nautilus shell resulting from the initially evolute condition and occupying the axis of the coil. 54. 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
