- stamens,
numerous free
carpels in a
single whorl, each with 1 ovule, and
subventral styles. The
fruit is an
achene with a
short beak. The
nineteenth century...
- with a
small perforation in the center,
shallow dorsal impression, and
subventral tubular siphuncle with thin
connecting rings.
Chambers are very short...
- apex and
sutures are
straight or have
lateral lobes. The
siphuncle is
subventral,
orthochoanitic with short,
straight necks and thin
connecting rings....
- The
aperture is
without a
hyponomic sinus. The
siphuncle is
small and
subventral.
Other Devonian Acleistoceratidae are Acleistoceras, Paracleistoceras...
- of the
buccal capsule. It also has a pair of
subdorsal and a pair of
subventral teeth located close to the rear.
Males are
usually 7–9 mm long, whereas...
-
slightly or
moderately and have thin walled,
orthochoanitic marginal or
subventral,
tubular siphuncles (Sweet 1964). The
Graciloceratidae was
proposed by...
-
elliptical transverse aperture,
without a
hyponomic sinus, and a small,
subventral siphuncle. The
phragmocone is
rapidly expanding and
strongly exogastric...
-
Sutures are
transverse but may form
broad lateral lobes. The
siphuncle is
subventral -
close to the
outer rim;
necks are straight,
connecting rings slightly...
-
rounded saddles then
smaller lobes just
above the
umbilical seam;
siphuncle subventral.
Found in
Europe and
North Africa. An
almost perfect homeomorph of the...
- of the
buccal capsule. It also has a pair of
subdorsal and a pair of
subventral teeth located close to the rear. Historically, the
European medicinal...
