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WILLIAM MACNAE
the three major drainage systems. For example, the faunas of northern
Sumatra (Atjeh) and western Malaya have strong affinities. Likewise
those of southeastern Sumatra, Java, and south Bornco. Not enough
evidence is presented t o show similar affinitics between northern
Borneo, eastern Malaya and South East Asia.
3. Division 4. North-eastern extensions
The fourth division comprises the northern and eastern extensions of
mangroves into Taiwan, South China, and the Ryfi-Kyfi Islands and an
extension of the fauna associated with mangroves into subtropical
Japan. So far as the mangroves themselves are concerned it is an area
of progressive subtraction and the same is to some extent true of the
fauna. Balss (1924) claimed that most of the tropical crustaceans fell
off sharply along the chain of the Ryfi-Kyil Islands. However, his
lists of crustaceans from these islands contain no mangrove-associated
species apart from Thalassina anomala. But taken by and large this is
apparently true also of mangrove-associated molluscs such as species
of Polyrnesoda (Geloina), Terebralia sulcata, T . paldstris and species of
Melampus. None of these reach southern Japan, but Oyama (1950)
records that representatives of these genera and other mangroveassociated molluscs have been found fossil in Tertiary rocks in southern
Japan. He also records similar deposits containing such shells even of
modern species in Pleistocene deposits in Taiwan.
Ono ( 1965) reports several ocypodids reaching Kyiishii Island,
Japan, including Uca lactea, Scopimera globosa and Ilyoplax pusilla, all
mangrove-associated crabs. Scylla serrata reaches Hong Kong and
Hankow (which is some hundreds of miles up the Yangtse river).
4. Division 5. Celebes, eastern Borneo and the Moluccas
The fifth division comprises most of the islands between the edges
of the Sunda and Sahul shelves. Van Benthem Jutting (1959a) gives an
analysis of the distribution of freshwater and brackish water molluscs
from the Moluccas, and shows that while the ellobiids have a very wide
distribution only a few have western affinities but a greater proportion
have eastern aEnities, i.e. with the fauna of New Guinea. I n earlier
papers she shows that the fact that these islands were never connected
to the islands comprising Sundaland has restricted the freshwater
faunas of Celebes and the Moluccas.
It is certain that this area could have been invaded by representatives of the more purely west-Pacific elements as well as by purely
Indian Ocean elements over a long period, as these islands were not
affected greatly by Pleistocene changes in level.
WILLIAM MACNAE
the three major drainage systems. For example, the faunas of northern
Sumatra (Atjeh) and western Malaya have strong affinities. Likewise
those of southeastern Sumatra, Java, and south Bornco. Not enough
evidence is presented t o show similar affinitics between northern
Borneo, eastern Malaya and South East Asia.
3. Division 4. North-eastern extensions
The fourth division comprises the northern and eastern extensions of
mangroves into Taiwan, South China, and the Ryfi-Kyfi Islands and an
extension of the fauna associated with mangroves into subtropical
Japan. So far as the mangroves themselves are concerned it is an area
of progressive subtraction and the same is to some extent true of the
fauna. Balss (1924) claimed that most of the tropical crustaceans fell
off sharply along the chain of the Ryfi-Kyil Islands. However, his
lists of crustaceans from these islands contain no mangrove-associated
species apart from Thalassina anomala. But taken by and large this is
apparently true also of mangrove-associated molluscs such as species
of Polyrnesoda (Geloina), Terebralia sulcata, T . paldstris and species of
Melampus. None of these reach southern Japan, but Oyama (1950)
records that representatives of these genera and other mangroveassociated molluscs have been found fossil in Tertiary rocks in southern
Japan. He also records similar deposits containing such shells even of
modern species in Pleistocene deposits in Taiwan.
Ono ( 1965) reports several ocypodids reaching Kyiishii Island,
Japan, including Uca lactea, Scopimera globosa and Ilyoplax pusilla, all
mangrove-associated crabs. Scylla serrata reaches Hong Kong and
Hankow (which is some hundreds of miles up the Yangtse river).
4. Division 5. Celebes, eastern Borneo and the Moluccas
The fifth division comprises most of the islands between the edges
of the Sunda and Sahul shelves. Van Benthem Jutting (1959a) gives an
analysis of the distribution of freshwater and brackish water molluscs
from the Moluccas, and shows that while the ellobiids have a very wide
distribution only a few have western affinities but a greater proportion
have eastern aEnities, i.e. with the fauna of New Guinea. I n earlier
papers she shows that the fact that these islands were never connected
to the islands comprising Sundaland has restricted the freshwater
faunas of Celebes and the Moluccas.
It is certain that this area could have been invaded by representatives of the more purely west-Pacific elements as well as by purely
Indian Ocean elements over a long period, as these islands were not
affected greatly by Pleistocene changes in level.