鳗类，鳗：无颚的各种原始水生圆口纲脊椎动物中的一种，包括七鳃鳗和盲鳗。

Any of various primitive aquatic vertebrates of the class Cyclostomata, lacking jaws and including the lampreys and hagfishes.

youdao

与八目鳗类鱼区别开的七鳃鳗。

Any of several similar fishes, such as the lamprey and electric eel.

youdao

七鳃鳗隶属于圆口纲，是一类因营半寄生生活而引发机体显著特化的动物。

A commensal organism, especially an insect that lives in the nest or burrow of another species.

youdao