Pseudocycnidae

例句：

1. 1.The pseudocycnids are a group of marine animals that live in the deep sea.
   伪海鞘纲是一类生活在深海的海洋动物。
2. 2.Pseudocycnidae is a family of cephalopods that includes the squid and cuttlefish.
   伪海鞘纲是一类头足纲动物，包括鱿鱼和章鱼。
3. 3.The pseudocycnids have unique adaptations for living in extreme environments.
   伪海鞘纲具有适应极端环境的特有适应性。