Cameral depostis are well developed on the convex side, toward the apex while only thin on the concave side, making the curvature exogastric.
22.
Plectronoceratoids are generally small to tiny forms with orthoconic or endogastric shells, a few being exogastric, with proportionally large ventral siphuncles that contain numerous diaphragms.
23.
Late Cambrian " Huaiheceras " ( Hauiheceratidae ) is also similar in being long with a small marginal siphuncle, but is exogastric and less strongly curved.
24.
The shell, or conch, of " Cyrtocycloceras " is a moderately expanding annulated exogastric cyrtocone, with curvature like that of a rocking chair rocker.
25.
Protocycloceratidae, named by Kobayashi ( 1935 ), are characterized by transversely ribbed, elongate shells that may be straight or slightly curved, as to be either endogastric or exogastric.
26.
The shell of " Teichertoceras " is moderately compressed; the early portion a narrow expanding cyrtocone that in the adult become more swollen, taking on an exogastric aspect.
27.
""'Pentameroceras " "'is a straight to slightly exogastric breviconic oncocerid from the middle Silurian of North America and Europe belonging to the Trimeroceratidae.
28.
The second, formed by the Westonoceratidae, Lowoceratidae, and Discosoridae, are fundamentally exogastric with the siphuncle near the outside or longituninally convex curvature, although the Discosoridae are somewhat different.
29.
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.
30.
""'Mecynoceras " "'is a Late Devonian oncocerid included in the Poterioceratidae, a family of subcircular to compressed exogastric cyrtocones without a hyponomic sinus.
