Crassostrea lacerta

The Crassostrea lacerta is a fairly thin shell, measuring up to 5 cm long. It is equivalve, inequilateral, and varies in shape from being long and narrow to being broadly circular, thus being highly irregular and often distorted. It often grows attached to each other in colonies which increases this irregularity and distortion. The color of the shell is usually a purplish-brown, but older more worn out and faded specimens may be a light brown. One shell found was black and in some places had worn away to reveal the yellow-brown undercoat, thus appearing mottled. The interior of shell is smooth and glossy. There are 5-8 weak radial ribs (often inconspicuous) and the ventral margin between these ribs is greatly indented, thus resembling a duck’s foot. These ribs and the indentations in the ventral margin are not so obvious in the long narrow forms. The ribs may bear nodules along their lengths. There is a prominent chondrophore. Single valves were very common and colonies, sometimes living, were commonly found cemented to Tonna, Pugilina, and many other shells.