Illustrations and objective data courtesy of AMOCO Production Co., Alan B. Shaw (Manager, South Florida Carbonate Project), and Brian F. Glenister (AMOCO Consultant)

A1. Shape

General shape of the shell
Character State Definition Illustration
equivalve Right and left valves subequal and comprising mirror images of one another except for hinge structures

inequivalve Opposite valves dissimilar in size or shape or both
prosogyral Beaks directed forward

Beaks turned backward instead of projecting forward

In this case, you use the fact that the beak is closer to the anterior rather than the fact that the beak points to the posterior of this shell. This is a picture of the left valve, not the right valve.

taxodont Characterized by more or less numerous subequal hinge teeth, generally arranged in a row
mytiliform Slipper-shaped
auriculate Shell possessing auricles; equivalent to alate
produced Shell much elongated in one direction
prosocline Having forward obliquity, approach to beak along mid-line of shell inclined forward

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Last updated on September 3, 2002-eek.