在这篇论文里，海克尔用手笔画下了他所观察到的多种动物早期胚胎的形象。

In his paper, Haeckel drew by hands the morphological features of early embryos of several animal species.

youdao

在这篇论文里，海克尔用手笔画下了他所观察到的多种动物早期胚胎的形象。

In his paper, Haeckel drew by hands the morphological features of early embryos of several animal species.

youdao