Juvenile shell outline has a really different aspect compared with the adult specimen so that Coen (1934) set up the new species Clathroconcha istriensis just basing himself on premature specimens (2.5 mm) of Ctena decussata collected at Rovigno d'Istria (upper Adriatic - Italy). In 1973 G. Barsotti proved it dealt with the same species comparing the hinge and pallial scars. Indeed juvenile shells have a sinus on the posterior upper margin near the umbo, disappearing in adult specimens which assume a roundish outline, more or less suborbicular. The average width is about 15-16 mm. The valve anterior and posterior ends are sometimes rust-coloured (JIavida. Montcrosato). Usually the shell is white-greyish or yellowish in colour (clear blue caeruleans. described by Monterosato).

Habitat: this species prefers organic detrital bottoms. Distribution: common all over the Mediterranean.