-
breviconic s****, with an
elliptical transverse aperture,
without a
hyponomic sinus, and a small,
subventral siphuncle. The
phragmocone is
rapidly expanding...
-
development of a
protruding neck
ending at the aperture, both
ocular and
hyponomic sinuses which form when
fully grown, and
camerae that are
mostly confined...
- a
black layer along the
apertural margin and the
accentuation of the
hyponomic and
ocular sinuses. The
exterior body
chamber lacks colour banding. The...
-
Apertures vary from
round to T-shaped, with a long narrow, ventral,
hyponomic sinus for the
maneuvering funnel.
Siphuncles are
commonly central or subcentral...
- frills, each of
which is bent
apically so as for form a well
defined hyponomic sinus, but are
without spoutlike or
spinose projections. Halloceras, from...
- S**** are depressed,
irregularly annulated cyrtocones with V-shaped
hyponomic sinuses,
ornamented by
longitudinal and
transverse ridges.
Position and...
-
laterally and ventrally, with a
small to
occluded umbilicus,
broadly rounded hyponomic sinus, only
slightly sinuous sutures, and a
small siphuncle that is variable...
-
transversely marked, or
laterally costate s****, with a con****uous
hyponomic sinus.
Early whorl sections tend to be subtriangular;
become broader and...
- the
siphuncle ventral, empty. The
peristome (aperture rim) has a
broad hyponomic sinus -for the
hydrojet funnel,
ventrolateral projections, dorsolateral...
-
profiles both convex.
Aperture contracted and
visored with a long
ventral hyponomic sinus, 2
pairs of
shorter dorsolateral sinuses, and a
short dorsal salient...
