Freshwater crab Nature (IUCN); of the species for which data are available, 32% are threatened with extinction. For instance, all but one of Sri Lanka's 50 freshwater crab species are endemic to that country, and more than half are critically endangered. Freshwater crab There are around 1,300 species of freshwater crabs, distributed throughout the tropics and subtropics, divided among eight families. They show direct development and maternal care of a small number of offspring, in contrast to marine crabs which release thousands of planktonic larvae. This limits the dispersal abilities of freshwater crabs, so they tend to be endemic to small areas.
Malacological Society of London 1942. Molluscs range in size from cephalopods such as the octopus and giant squid to microscopic gastropod snails, and the Society is concerned with some 85,000 recognised extant species, which include 23 per cent of all named marine organisms as well as molluscs living in freshwater and terrestrial habitats. It is also interested in the species (including those of the two extinct classes of molluscs) preserved as fossils, which creates a relationship with the study of geology. In association with the Oxford University Press, the Society publishes the "Journal of Molluscan Studies", previously called "Proceedings of the Malacological Society", and