中文摘要：

在陕南寒武系底部的宽川铺段不仅保存了大量的小壳化石，而且还有诸多后生动物的卵和胚胎化石。目前，大量的胚胎化石已被报道，但是对古老的后生动物早期的个体发育却鲜有报道，尽管Bengtson和Yue（1977）建立了Olivooides的发育序列，但仍缺少一些重要的中间环节，而且胚胎的早期卵裂阶段还不是很清楚。因此，Olivooides和Punctatus之间的联系很难确立。本文报道了宽川铺生物群中新发现的精美的Punctatus的卵裂期、囊胚期及孵化幼体阶段的胚胎化石标本，这些新发现不仅填补了Punctatus发育序列中的空白，而且揭示了Olivooides和Punctatus之间的联系。这些新收集的Punctatus的卯裂期和孵化期的化石特征及Punctatus的形态学证明了Punctatus不是浮游生物，而是底栖生物。大量的胚胎化石和Punctatus的孵化幼体化石标本为我们研究后生动物早期演化提供了线索。

英文摘要：

In south Shaanxi, China, the lowermost Cambrian-Kuanchuanpu Formation contains not only abundant small shelly fossils but also metazoan eggs and embryos. Knowledge of these fossil embryos has increased dramatical- ly, but relatively little information has been reported concerning the early ontogeny of ancient Metazoa. Although the developmental sequence of Olivooides has been reconstructed by Bengtson and Yue （1997）, some crucial developmental stages are still obscure and the embryos of early cleavage stages are uncertain. Accordingly, it has been difficult to re construct the relationship between Olivooides and Punctatus. Here we report some new exquisitely preserved fossils of cleaving-stage embryos, juvenile stage and hatched individuals of Punctatus from the Kuanchuanpu fauna. These new findings not only fill gaps of Punctatus developmental sequence, but also reveal the relationships between Olivooides and Punctatus. All the characteristics of newly collected Punctatus hatchings and the morphology of the hatched Punctatus suggests that it was not pelagic, but rather benthic. The exceptionally well preserved embryos and hatchlings of Punctatus provide important clues about the early evolution of metazoans in general.