Up until this point, all cephalopods had been members of the slow and steady group known as nautiloids, from the pioneering little Plectronoceras to the imposing Cameroceras.

在此之前， 所有头足类动物都属于被称为鹦鹉螺的缓慢而稳定的类群，从开创性的小型 Plectronoceras 到雄伟的 Cameroceras。