-
elliptical transverse aperture,
without a
hyponomic sinus, and a small,
subventral siphuncle. The
phragmocone is
rapidly expanding and
strongly exogastric...
- The
aperture is
without a
hyponomic sinus. The
siphuncle is
small and
subventral.
Other Devonian Acleistoceratidae are Acleistoceras, Paracleistoceras...
- sinuous;
siphuncle large,
subventral,
apparently orthochoantitic[clarification needed] with
tubular segments. The tubular,
subventral siphuncle separates Chidleyenoceras...
- with a
small perforation in the center,
shallow dorsal impression, and
subventral tubular siphuncle with thin
connecting rings.
Chambers are very short...
- large, 1/3 to 1/2 the s**** diameter;
ventral at the beginning,
becoming subventral in the
adult portion.
Septal necks are
holochoanitic to
slightly maxichaonitic...
- 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...
-
possessing short outer labial setae; its
short pharynx;
carrying anterior subventral teeth and a
posterior dorsal tooth in the same
stomal chamber; having...
- 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...
-
outside curve. The s**** is
elongate and slender,
wider than high, with a
subventral, empty,
cyrtochoanitic siphuncle, with
segments somewhat expanded into...
- apex and
sutures are
straight or have
lateral lobes. The
siphuncle is
subventral,
orthochoanitic with short,
straight necks and thin
connecting rings....
