crinoids

Everyone knows that some terrestrial animals are active primarily at night and sleep most of the day, while others go about their business during daylight hours and rest when it's dark. For some reason, many people are surprised to learn that the same thing holds true for animals that live in the sea. One of the many marine animals that works the night shift is the crinoid species pictured here: Lampometra klunzingeri, a member of the Mariametridae family. During daylight hours, these crinoids hide in crevices in the reef. Shortly before sunset, like clockwork, they emerge from their…

Crinoids, a class of marine animals in the phylum Echinodermata, are pretty creatures. The photo at right shows a crinoid perched on a Malaysian reef with its fluffy arms extended for feeding. Looking at the photo, it's easy to see how they acquired their common name, Feather Stars. This is how divers usually see crinoids, and this is how they are most often photographed. As pretty as crinoids are -- and they come in a vast array of colors -- photographs of the whole animal don't reveal much about the animal's structure or behavior. Whole-animal photos of creatures like this should be…