簡介:"CheiruridaeIntroductionPleurae with pointed or bluntly rounded spines and oblique or transverse pleural furrows, in some genera represented by row of pits, or effaced. Pygidium with 2 to 4 pairs of pleural ribs and spines; axial rings few. Surface commonly tuberculate, pitted, or both. Appendages only of Ceraurus described; antennae uniramous, other appendages biramous, with gill branches bearing filaments only on distal segments (178, 359). L.Ord.(Tremadoc.) - M.Dev. 簡介 肋末端有尖刺或鈍刺;肋溝橫過或斜過肋節,有些肋溝由小坑洞組成,有些肋溝消失。尾部有2到4對肋節及邊緣刺,軸節少。表面通常佈有粒狀突起、小坑洞或兩者皆有。生存於早奧陶紀至中泥盆紀。 "