One of the earliest recorded species of radiolarians, characterized by a siliceous shell, and a member of a family whose members have a spherical or ellipsoidal shape and no internal spicule. H. vetustum is known from the Ordovician of Europe.
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。