AN ANALYSIS OF SHELL OCCUPATION BY TWO SYMPATRIC SPECIES OF HERMIT CRAB. I. ECOLOGICAL FACTORS.

Three series of experiments were conducted on Pagurus longicarpus and Clibanarius vittatus at Beaufort, North Carolina. The first series showed that the preferred species of shell by either species of crab is determined by the size of the crab and that certain species of shells are not available in preferred numbers for the hermit crab species. This affects C. vittatus more than P. longicarpus. The second series showed that shell fighting is not an important factor in determining which species occupies which kind of shell while the third series showed that a substrate preference for mud by P. longicarpus may limit it from obtaining a preferred species of shell that occurs naturally on sand.