Wade ( 1988 ) instead proposed separating the Nautiloidea into phylogenetically related superorders while retaining the basic concept of the subclass : externally shelled cephalopods with simple concave septa and retrochoanitic siphuncles from which the convexly septate Ammonoidea with prochoanitic siphuncles are distinguished.
12.
It consists at one end of a convexly tapered lime is held in the other, is a relatively new adaptation of the traditional glass or plastic citrus reamer ( with a juice rim ) that was placed on a table and pressed downward.
13.
"" Meketibolodon " ( Hahn 1993 ) is distinguished from the other genera [ of Paulchoffatiidae ] by two characters : the tooth row is significantly convexly curved upwards, and the corpus mandibulae has angled margins ventrally ( Hahn and Hahn 1998b ).
14.
(Description by Joseph Verco ) The solid, elongate-fusiform shell consists of 6?lip is solid but sharp, with a deep round sinus separated from the ascending suture by a callus from the posterior part of the inner lip, then straightly convexly antecurrent to two shallower sinuses at the base of the siphonal canal.
