Mr. Busk, however, does not know of any gradations now existing between a zooid and an avicularium.

然而，布斯克先生不知道目前在类动物和鸟嘴之间存在任何等级。

The avicularia, like the vibracula, probably serve for defence, but they also catch and kill small living animals, which, it is believed, are afterwards swept by the currents within reach of the tentacula of the zooids.

avicularia 和 vibracula 一样， 可能起到防御作用， 但它们也捕捉并杀死活体小动物，据信，这些动物随后会在类动物的触手可触及的范围内被水流冲走。