The caudal limb of the postcentral is joined by a transparietal piece.
So they got more tail and spliced it on to his caudal appendage.
He named it falcata, or "scythe-shaped," from the curving of the caudal fin.
The caudal extremity of both is furnished with a rudimentary claw.
This brings you to where the dorsal and caudal fins are inserted.
They are last traceable on the eighth or ninth caudal (vertebra 35 or 36).
A small common central rod separates the two united pectoral feet from the two other spines (the caudal foot and the apical horn).
Three feet latticed, conical, nearly parallel and vertical (the caudal curved), about half as long as the breadth of the shell.
The two lateral feet (right and left) are larger and more branched than the two sagittal feet (sternal and caudal foot).
Basal ring of about the same size as the mitral ring, with three large and stout divergent feet (two lateral and one caudal).