All the ammonites vanished, but their cousins the nautiloids, who lived similar lifestyles, swam on.

菊统统消失了，但它们的表亲鹦鹉螺目软体物却存活下来，尽管它们有着相似的活方式。

Unlike nautiloids, which grew slowly and invested a lot of energy into making a few offspring, ammonites grew quickly and had many offspring.

与鹦鹉螺缓慢并投入大量精力制造少数代不同，菊迅速且代众多。

The nautiloids were probably saved by their slow and steady lifestyles, and six species in two genera have survived to the present day.

鹦鹉螺可能是因其缓慢而稳定的活方式而得救，两个属的六个物种存活至今。

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。

At the end of the Cretaceous Period, a fatal blow struck the ammonites and most of the nautiloids: the Cretaceous-Paleogene extinction event -- the same event that killed the non-avian dinosaurs.

在白垩纪末期，一个致命的打击击中了菊和大多数鹦鹉螺：白垩纪-古近纪灭绝事件——与杀死非鸟类恐龙的事件相同。

Nautiloids today, as ammonites would have done, control their buoyancy, just like a submarine, by emptying the chambers of water to be able to float and refilling them to be able to sink.

今天的鹦鹉螺，就像菊会做的那样，控制它们的浮力，就像潜水艇一样，通过排空腔室中的水以便能够漂浮，并重新用水填充腔室以便能够下沉。