|One of the many deep-sea species found in Phylum Ctenophora. This species is bioluminescent.|
|A larvae with a colored body|
Ctenophores are commonly referred to as comb jellyfish thanks to another of their characteristic features. Every Ctenophore has rows of cilia known as ctenes or combs organized into eight bands along the body called costae or comb rows. This is their primary method of movement and most species are only weak swimmers, unable to swim against a strong current. This makes them planktonic, despite the large size of some species. In combination with the combs, a sense organ opposite of their mouth is used to detect their orientation and controls how quickly the different costae beat.
|A bioluminescent species|
There is still much that isn't known about Ctenophores thanks to most species only being found in open ocean. Often, observations are chance encounters where individuals are caught in fishing nets. It isn't uncommon for scientific expeditions that are specifically looking to study these animals to discover new species during their searches.
Source is Biology of the Invertebrates. Images are from Wikimedia Commons and are under Creative Commons licenses or are copyright free: one, two, three, four, five.