Further additions to the knowledge of Indo-Pacific Mollusca in the Mediterranean Sea (Lessepsian migrants) By AI. Barash and Z. Danin Summary ^) A report on 29 Indo-Pacific species found in the Mediterranean is presented. These species have not been discus-sed in the general reports on the migrations of Indo-Pacific species published by G. HAAS (1948), GhisoTTI (1974), Barash and Danin (1973) and in various articles on the migrating species collected during 1971-1984. The 29 species recorded in the present report belong to 1 9 Gastropoda (Prosobranchia -10, Opisthobranchia -9) and to 10 Bivalvia (Pteriomorphia -3, Heterodonta -7). The majority of the presented species (22) have been collected only close to the Suez Canal, along the Mediterra-nean coasts of Israel and Sinai. 7 species are recorded only or also from sites outside of Israel and Sinai: Black Sea, Aegean Sea, Adriatic Sea, lonian Sea, Tyrrhenian Sea. The greatest part of the Indo-Pacific species in the Mediterranean (79 of 91) are from the Erythrean subregion. A smaller part (12 species) were not recorded from the Erythrean subregion, but from areas in the Indo-Pacific remote from the Mediterranean. It is unlikely that these species would be able to reach the Mediterranean in larval stage, since the life span of moUuscan larvae is rather limited. It is assumed that certain migrants were transported in adult stage by carriers (ships, fishes etc). Of the 91 Indo-Pacific species appearing in the Mediterranean, 44 species have been collected as one or a few Shells. The shells may be brought occassionally into the Mediterranean and it is doubtful if we can consider these species as inhabitants of this sea. 47 species were found live or in great numbers of shells, they may be regarded as re-sidents in the Mediterranean. The foUowing 13 species may be qualified as permanent inhabitants in the Mediterranean: Diodora rueppelli, Mi-nolianedyma, Pirenella cailliaudi, Cerithmm scabridum, Rhinoclavis kochi, Thais carinifera, Bursatella leachisavi-gniana, Hypselodoris infucata, Brachidontes variabilis, Pinaada radiata, Malleus regula, Paphia textile and Gast-rochaena cymbium. Based on the data accumulated since the opening of the Suez Canal (1869) it may be stated: 1). The number of im-migrating molluscan species has increased gradually during the past years . 2) . The great majority of the Indo-Pacific immigrants are concentrated in the Eastern Mediterranean. A few penetrated the Western Mediterranean but did not surpass the Siculo Tunisian threshold. Introduction Several summary reports devoted to the migration of Indo-Pacific moUusca into the Mediterranean have been pubHshed during this Century by G. Haas (1948), Ghisotti (1974b) and Barash & Danin (1973, 1977). Numerous articles on separate Indo-Pacific species collected in the Mediterranean during 1971-1984 have been published by H. K. Mienis and by other authors. The species Melibe fimbriata, recorded in the addendum, was not included in the lists of the paper. 117
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