Main Page | See live article | Alphabetical index The Mesozoa are animals without a full metazoan organization. At one time they were classified as a phylum, but are now generally believed to be unrelated to one another, so the term mesozoan is applied descriptively rather than taxonomically. The two main mesozoan groups are the Rhombozoa and Orthonectida. This article is from Wikipedia. All text is available under the terms of the GNU Free Documentation License.