The signature feature of Weissenborn guitars is the hollow neck, effectively a highly adapted body chamber that runs the entire length of the body, making conventional playing completely impossible.
32.
Nostoceras is typified by a tightly coiled helical spire on a large U shaped body chamber with the aperture, in mature individuals, nearly touching and lying underneath the spire.
33.
Flower 1943 : slender, compressed, regularly expanding, body chamber much longer than phragmocone; septa very close spaced, siphuncle small, subventral; " M-U Ord ", NAm . ( Sweet K383)
34.
""'Asymptoceras " "'is an aipoceratid genus ( Nautiloidea ) similar to " Aipoceras " but tightly coiled and with only part of the body chamber divergent from the previous whorl.
35.
"Perimecoceras " probably lived on the sea floor, body chamber horizontal, phragmocone behind arched upward away from the bottom, using a combination of crawling and jet-swimming as it moved about.
36.
This cephalopod produced a straight to slightly exogastric shell with a variable cross section that is generally circular, in which septa are close spaced and transverse, the body chamber is inflated.
37.
"' Juraphyllitidae "'is a family of Lower Triassic phylloceratin ammonites from Europe, North Africa, and Asia characterized by narrow, evolutely coiled shells, usually with coarse ventral ribbing on the body chamber.
38.
The dorsal profile changes from concave in the apical portion to straight, then slightly convex at the front of the phragmocone and back of the body chamber, the concave again near the aperture.
39.
""'Vesperoceras " "'is a medium size, generally straight, breviconic mandaloceratid with a broad annular expansion to the anterior part of the phragmocone followed by a constriction at the base of the body chamber.
40.
The shell of " Arctohungerites " is subdiscoidal, involute, with a rounded venter, weak sigmoidal folds on the body chamber and a distinct ventral keel on the distal end of the chambered portion.
