Cydippids

Cydippids are a class of comb jellies, belonging to the phylum Ctenophora. They are free-swimming marine invertebrates characterized by their transparent, gelatinous bodies. Unlike true jellyfish, cydippids do not possess stinging cells (nematocysts). Instead, they capture prey using sticky tentacles. These tentacles are often long and retractable, and can be covered in colloblasts, specialized cells that secrete a sticky substance.

Cydippids move through the water using rows of cilia, which are arranged in comb-like plates called ctenes. The beating of these cilia creates iridescent flashes of light, giving comb jellies their common name. Their bodies are typically oval or spherical, and they lack a centralized nervous system, instead possessing a nerve net.

Reproduction in cydippids is usually hermaphroditic, meaning individuals possess both male and female reproductive organs. They release eggs and sperm into the water column for external fertilization. The resulting larvae are planktonic and develop into juvenile cydippids.

These creatures are found in all the world's oceans, from tropical to polar waters, and from the surface to the deep sea. They are an important part of the marine food web, feeding on small planktonic organisms and being preyed upon by larger animals. Examples of cydippids include species within the genus Pleurobrachia, commonly known as sea gooseberries.