a fossil marine arthropod that occurred abundantly during the Palaeozoic era, with a carapace over the forepart, and a segmented hindpart divided longitudinally into three lobes 三叶虫
Subphylum Trilobita, phylum Arthropoda: numerous classes and orders 三叶虫亚门,节肢动物门:众多纲和目
语源
mid 19th cent.: from modern Latin Trilobites, from Greek tri- 'three' + lobos 'lobe'