Dentist specialties are recognized in those areas where advanced knowledge and skills are essential to maintain or restore oral health. The list of recognized dental specialties differs from country to country.
In contrast, radially symmetrical animals like jellyfish have a topside and a downside, but no identifiable front or back. The bilateria are a major group of animals, including the majority of phyla but not sponges, cnidarians, placozoans and ctenophores. For the most part, bilateral embryos are triploblastic, having three germ layers: endoderm, mesoderm, and ectoderm.
List of 11 Important Phylum | Animal Kingdom. 1  1. Phylum Protozoa (Approximately 30,000 Known Species): 2  2. Phyllum-Porifera (Approximately 5000 Known Species): 3  3. Phylum Cnidaria (Approximately 10,000 Known Species): 4  4. Phylum Ctenophora (Approximately 80 Species): 5  5. Phylum Platyhelminthes (Approximately 6500 Known Species): Flat-worms, Flukes and Tape-worms. These are flat, un-segmented, worm-like creatures with soft and bilaterally symmetrical body. In a bilaterally symmetrical animal there is a right side and a left side, a fore end and a hind end, a dorsal or back surface and a ventral or front surface.