提示：点击例句中的单词，就可以看到词义解释

Petromyzontidae lack centra and have a persistent notochord .

七鳃鳗科缺乏中心椎盘而且有一个连续的脊索。

Comprises true vertebrates and animals having a notochord .

包含真正的脊椎动物和脊索动物。

Fishlike animals having a notochord rather than a true spinal column .

有脊索但无真正的脊柱鱼类动物。

Study suggests possible role of embryonic cells from the notochord of dogs to regenerate disc cartilage .

研究提示源自犬脊索的胚胎细胞对椎间盘软骨有再生作用。

We also give the computer simulation method of notochord development in the african frog xenopus laevis .

本文还介绍了非洲爪蟾脊索器官形成的计算机仿真方法。