urochord

• 指一类原始海洋脊索动物，身体呈囊状、不分节，其特征是终生或仅在幼体阶段具有脊索；也可特指尾索动物幼体的脊索，通常局限于尾部区域。

A noun referring to a primitive marine animal with a saclike, unsegmented body, characterized by a urochord that is prominent in the larval stage, or specifically the notochord of a larval tunicate typically confined to the caudal region.

1. C2formalscientific

   A primitive marine animal with a saclike, unsegmented body and a prominent urochord visible in the larval stage.

   尾索动物

   • The urochord is a fascinating example of early chordate evolution.
   • Marine biologists study the urochord to understand the development of the backbone.
   • The larval urochord displays a distinct tail structure.

   同义词tunicateurochordate

2. Larval notochordC2formalscientific

   The notochord of a larval tunicate, typically confined to the tail region.

   幼体脊索

   • The urochord provides structural support in the larval tunicate.
   • During metamorphosis, the urochord is reabsorbed.
   • The presence of a urochord is a key characteristic of tunicate larvae.