bivalve rectal speculum

例句：

1. 1.The bivalve shell is a common feature of many marine organisms.
   双壳类动物的贝壳是许多海洋生物的常见特征。
2. 2. The bivalve mollusks are known for their unique shell structures.
   双壳类软体动物以其独特的壳结构而闻名。
3. 3. The bivalve mollusks play an important role in the ecosystem.
   双壳类软体动物在生态系统中起着重要的作用。