When put in a glass container they can be kept alive for many days. One of the most obvious characteristics are the locomotory organs, eight rows of comb-like structures that show irridescent colours when they reflect direct sunlight. They are real predators. With it's long tentacles it captures food like copepods, the larvae of many organisms and other small creatures floating in the plankton. It brings the food to it's mouth which is shown in the pictures at the head of this article.
Most textbooks however show the organism with it's mouth facing downward.
I always see them with the tentacles pointing down. One row of combs under the microscope. When I was recently studying some plankton samples I saw this very tiny egg. It was no more than half a millimetre but to my surprise contained a larva of a ctenophore. All body organs were already there.