三叶虫是很多人耳熟能详的远古动物。它们是化石中的明星,地位仅次于恐龙。三叶虫是节肢动物门中已经灭绝的三叶虫纲中的动物。在所有的化石动物中三叶虫是种类最为丰富,至今已经确定的有十个目,两万多个种。三叶虫只在海相地层中发现,至今没有在陆相地层中发现过,这说明三叶虫是海洋动物。三叶虫的身体从上往下可以分为头部、胸部和尾部。它们身体分节,有带沟将身体分为中轴及左右对称的 Trilobite is an ancient animal familiar to many people. They are the stars in fossils, second only to dinosaurs. Trilobite is an extinct trilobitid in the arthropod door. In all fossil animals trilobite is the most abundant species, has been identified to have 10 orders, more than 20,000 species. Trilobites are only found in marine formations and have not been found in continental strata until now, indicating that trilobites are marine animals. Trilobite body from top to bottom can be divided into head, chest and tail. They are body parts, with grooves to divide the body into symmetrical axes