- were
straight (orthoconic),
others curved (cyrtoconic); some were long (
longiconic),
others short (breviconic). Some long-s****ed
forms like
Endoceras attained...
-
Pseudorthocerida is an
order of
generally straight longiconic orthoceratoids with a
subcentral to
marginal cyrtochoanitic siphuncle composed of variably...
- as a
family within the
Oncocerida to
include genera characterized by
longiconic orthocones and
cyrtocones with a
subtriangular to
depressed cross-section...
-
possibly Estonia that can be
recognized by its slender,
weakly endogastric,
longiconic and
annulate s**** and
large marginal siphuncle that
contains endocones...
- rings, are
broadly expanded.
Pseudogomphoceras is a large,
atypically longiconic mandeloceratid that
reflects its
reudemannoceratid ancestry. The subcentral...
-
included in the Geisonoceratidae. As with the orthocerids, its s**** is
longiconic,
siphuncle more or less central, and
chambers somewhat long. Note that...
-
Ascoceratidae is a
family of Ascocerida,
bizarre orthoceratoid cephalopods, with
longiconic,
deciduous early growth stages which undergo period truncation and an...
-
smooth and
compressed and vary in form. They may be
breviconic (short) or
longiconic (elongate),
straight (orthoconic) or
curved (cyrtoconic).
Cyrtoconic forms...
- the Nautiloidea.
Hemichoanella is
characterized by its straight,
smooth longiconic s**** with a
circular cross section,
large marginal siphuncle and sutures...
- Montyoceras. The
fully mature breviconic ascocerid, with the
juvenile longiconic portion discarded was no
doubt a
facile swimmer. The
dorsal chambers would...
