The suture resembles that of " Clydonautilus ", from which it must have been derived, except for the more highly developed median saddle and bifurcated dorsal lobe.
22.
The umbilical lobe, which lies between the lateral lobe and dorsal lobe, on either side, is about the same size ad the lobule dividing the first lateral saddle.
23.
In " C . britskii ", males also differ from females by having four white blotches on the caudal fin, two at the dorsal lobe and two at the ventral lobe.
24.
""'Sholakoceras " "'is an extinct sutures form broad ventral saddles with a slight, shallow lobe, very shallow lateral lobes, and a deep funnel-shaped dorsal lobe.
25.
The "'Rhiphaeoceratidae "'are a small family of Sutures bend forward on the outer rim, forming wide shallow ventral saddles and dip strongly to the rear on the inner rim, forming deep dorsal lobes.
