Abstract: 8610 A. Introduction
1. Characteristics and Ecology
The Phylum Mollusca, the second largest phylum of the animal kingdom, is made up of such forms as clams, mussels, oysters, snails, slugs, octopuses, and squids. The life cycle of mollusks varies from about 1 to more than 300 years.1 In numbers of species (about 100 000 living and 35 000 fossil), mollusks are second only to the arthropods. Their ecology also is very diversified. They have been able to live successfully in nearly all terrestrial, freshwater, and marine habitats, from the greatest depths of the ocean to the highest altitudes recorded for animal life.2,3 Mollusks are important ecologically and are a source of food for human beings around the world.