Living animals and empty shells have been collected in 55 samples from Mugu Lagoon, coastal southern California. The abundances and distributions of 73 molluscan species from the samples were studied in order to evaluate postmortem movement of shells. Although transportation is common across short distances within the lagoon, several lines of evidence indicate that most empty shells were buried about where they lived. Taxa collected alive are adequately reflected by the empty shells accumulating in the lagoon; whether live and dead, the specimens are compared on the basis of individual taxa, of whole communities (defined by numerical analysis), or of relative abundances within communities. Postmortem transportation within this environment is insignificant for most paleoec logical purposes.

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