仙虾：透明的淡水鳃足类的任何一种，无甲壳并且倒置游动。

Fairy shrimp: any of various transparent freshwater crustaceans of the order anostraca that lack a carapace and characteristically swim upside-down.

youdao

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

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