The subkingdom that contains all animals (kingdom Animalia) possessing bilateral symmetry and three embryonic germ layers (the cells that will develop into the organs of the body). It is the largest animal subkingdom. Compare radiata.
科学参考收录了60776条科技类词条，基本涵盖了常见科技类参考文献及英语词汇的翻译，是科学学习和研究的有利工具。