-
ventral siphuncle with expanded,
nummuloidal segments.
Although also
torticonically gyroconic—having an out of
plane open
spiral -
Oxygonioceras differs...
-
mostly cyrtoconic as well as gyroconic, sepenticontic, and
sinstrally torticonic s**** with large,
typically straight necked (orthchoanitic) siphuncles...
-
largely abandoned Barrandeocerida.
Lechritrochoceratidae comprise dextrally torticonic genera with
costate s**** and
ventrally displaced siphuncles. Offset...
- cephalopods,
primitively coiled but
later forms may be cyrtoconic, gyroconic,
torticonic, and even breviconic, all
having empty siphuncles with thin connecting...
- s**** are
exogastrically or
endogastrically breviconic, planospiral, or
torticonic;
often with a
constricted or
visored aperture; and a
siphuncle commonly...
