lance.let
n.（名词）Any of various small, flattened marine organisms of the subphylum Cephalochordata, structurally similar to the vertebrates but having a notochord rather than a true vertebral column.Also called amphioxus 蛞蝓鱼类：任一种体形较小的头索动物纲的扁平海洋动物，它们在结构上与脊椎动物类似，但只有一个脊索而没有真正的脊椎也作 amphioxus
