- were
variable in form. Some were
straight (orthoconic),
others curved (
cyrtoconic); some were long (longiconic),
others short (breviconic). Some long-s****ed...
- some even tiny,
laterally compressed,
curved (
cyrtoconic) or
straight (orthoconic). Most
cyrtoconic forms are endogastric, with the
ventral side longitudinally...
- Reudemannoceras.
Paldoceras however is
rather dissimilar,
being more
strongly cyrtoconic (curved) and
lacking the
characteristic annulations.
Rousseau H Flower...
-
Middle Silurian to the Late Devonian. The
phragmocone of
Wadeoceras is
cyrtoconic (curved) and the
living chamber, more
orthoconic (straight).
Walter C...
-
embryonic s****.
Bactritida (Erben 1964) are
characterized by
orthoconic to
cyrtoconic s**** that may be long or
short with a
narrow siphuncle invariably in...
-
Galtoceras is a
cyrtoconic nautiloid from the
Middle Silurian of
North America,
named by
Foerste in 1934.
Galtoceras is
genus of the
Oncocerida and of...
-
Osbornoceras is a
genus of
Lower Silurian cyrtoconic nautiloid cephalopods known from Ohio and
possibly Manitoba, one of five
general currently included...
-
rapidly with a
tendency to
uncoil at maturity.
Juvenile forms are
somewhat cyrtoconic. The
apical end
forms a hook.
Aipoceras has been
found in
Lower Mississippian...
- (external s****)
shape is slender,
usually orthoconic (straight) or
weakly cyrtoconic (slightly curved). The
monophyly of
Riocerida as a
unique group is plausible...
-
characterized by a smooth,
exogastrically curved and
laterally compressed,
cyrtoconic to gyroconic, s**** with the
ventral margin the
outer rim. The venter...