Between January 1982 and December 1985, 65 species of Mollusca were co
llected from the Layari River, an ephemeral stream that bisects Karach
i. Gastropods were dominant followed by bivalves. The upstream region
is hypersaline and devoid of molluscs; the stretch within Karachi is h
eavily polluted and almost no living molluscs occur here.