In annelid 2 only , pin the following .

请只在环节动物2上以大头针标示下列构造。

To locate key features in a marine and a terrestrial annelid .

将一只海洋及一只陆生的环节动物特徵标出。

The first part of the alimentary canal of an arthropod or annelid , which includes the buccal cavity , esophagus , crop , and gizzard .

前肠节肢动物或环节动物的消化道的第一部分，包括口腔、食管、嗉囊和砂囊。