Phyla Mollusca and Annelida

click to find the answer to today's question What is the major limiting factor that would keep snails out of a body of water?

The trochophore larva of Mollusks

Members of these phyla have two things in common. They are the first animals we study that have a true body cavity, making them coelomates. They also have a similar embryonic development. The first stage of their larval development is a pear-shaped larva called a trochophore. link to a local picture

Phylum Mollusca

A snail Arizona representatives: