Species

Protostomes Coelomates Mouth develops from the blastopore Cleavage is radial and determinate ALL HAVE A TRUE COELOM! Subkingdom Eumetazoa Bilateral symmetry Coelomates Phylum Mollusca Soft bodied, with hard shell protection Ex: slugs, clams, snails, squids, and octopuses Open circulatory system ? fluid not always contained within vessels but circulates through hemocoel Most have exoskeletons Reduced or no segmentation Radula; rasping tongue to scrape food Many internal organs ? excretion through Three body parts Muscular foot - movement Visceral mass ? contains most of the organs Mantle ? secretes a shell An open circulatory system limits the size of these animals The closed circulatory system is much more efficient! Four classes of Phylum Mollusca