Science. 1972 Jul 21;177(4045):264-7. doi: 10.1126/science.177.4045.264.
Four Paleozoic bivalved genera are assigned to the new molluscan class Rostroconchia: Eopteria, Euchasma, Conocardium, and Pseudoconocardium. These mollusks have ani uncoiled univalved larval shell; an untorted bivalved adult shell; no hinge teeth, ligament, or adductor muscles; and a fused, almost inflexible. hinge. Rostroconchianis developed separately from the pelecypods through the ribeirioids, but are regarded as more closely related to the Pelecypoda and Scaphopoda than to other known classes of mollusks.
四个古生代双壳贝类属被归入新的软体动物类群——头足纲：Eopteria、Euchasma、Conocardium 和 Pseudoconocardium。这些软体动物具有未卷曲的单瓣幼虫壳；未扭曲的双瓣成体壳；无铰齿、韧带或收肌；以及融合的、几乎不可弯曲的铰合。头足纲是通过肋贝类与双壳类分开发展的，但与双壳类和头足类的关系比与其他已知的软体动物类群更为密切。
