They're called protostomes–Greek for " first mouth" .

它们被称为原口——希腊语中“第一个口”的意思。

When animals called protostomes, like insects, crabs, or earthworms, develop that tube, the first opening they make becomes their mouth.

当被称为原口动物的动物（ 如昆虫、 螃蟹或蚯蚓）发育出这个管子时， 它们打开的第一个开口就是嘴巴。

Fruit flies and humans are on opposite sides of a 670m-year-old division splitting bilaterally symmetrical animals into two groups: protostomes and deuterostomes.

果蝇和人类位于一个 670 米历史的分区的对立面，将双侧对称的动物分为两组：原口和后口。

This separation almost certainly predates the evolution of brains, meaning the brains of insects (which are protostomes) and those of vertebrates (deuterostomes) have separate origins.

这种分离几乎肯定早于大脑的进化，这意味着昆虫（原口动物）的大脑和脊椎动物（后口动物）的大脑有不同的起源。