shell variable in position b. Snails: (1) 2) 3) 4) c. “liver” gill mantle musele Octopus (one specimen): 3} . d. Hermit crabs: True crabs: 2) 2) 4) Species Differences. 3) "liver" gill muscle 1) digestive tract with contents 3) gill 2) 4) e. 2) “liver muscle carapace variable in position digestive tract with contents and (3) liver or gill muscle carapace variable in position There were not enough samples at any one island to reliably determine species differences. It is probable, however, that both species and individual differences are considerable as is indieated by the data from the two similar species of sea cucumbers presented in Table 8. At Rigili and Igurin where several specimens of crabs were taken (not more than two of one species), differences within a species are as great as between species. Tissue for tissue the land hermit crabs, Cenobita, may have a higher specific activity than the shore crabs. Conclusions. The most obvious and striking conclusion is that there was great variability in the amount of radioactivity found in invertebrates at every station sampled. The distribution of radioactive materials was evidently still in a state of considerable flux eight days after the shot. Surface contamination or the presence of radioactive material - 42 ~