A very rare shell, separated from the Anodonta on account of the hinge
being attenuated in the middle, and having small tubercles distributed
along its length. The substance is thicker and more solid than the
Anodonta, and of a brilliant rose-coloured pearly hue; it is found in
the rivers of warm countries.
Shell equivalve, inequilateral, transverse, with small apices; recurved,
but nearly erect; not auriculated; hinge very long, linear, crenulated
through all its length; ligament external and marginal; two well-marked
muscular impressions.
_I. exotica._ The exotic Iridina.
The only species of this genus answering to the above description.
FAMILY XIV.
CHAMACEA. Three genera.