Box Jellyfish (Class Cubozoa; sp. Chironex Fleckeri)
In addition to ocelli, like “normal” jellyfish, the dangerous box jellyfish also have true eyes—with a retina, cornea, and a lens. This allows them to see specific points of light, as opposed to only being able to tell between dark and light. They also retain the simpler pigment-cup ocelli, allowing them to see more.
They have limited memory, and a limited ability to learn.
Cleaning Symbiosis
If you’ve seen Finding Nemo, you probably remember the little french shrimp, Jacques. Jacques, a Pacific cleaner shrimp (Lysmata amboinensis), always made sure the tank was clean, and was appalled when everything was filthy. But, this behaviour is not limited to cartoon films—there are little Crustaceans all over the watery world, who like Jacques, enjoy “cleaning” their environment—and sometimes their fishy counterparts.
It has been observed that different species of fish will “line up” in a set up that’s similar to one would see at a car wash. The fish wait for their turn to be cleaned by little crustaceans and even some cleaner fish, like wrasses (Labroides dimidatus) and gobies (Genus Elacatinus). These cleaner fish/shrimp will remove and eat any parasites off the skin, both internally and externally.
There are many incredible parts to this cleaning symbiosis. Some of the fish that come to be cleaned would actually, under other circumstances, eat the cleaner fish or shrimp. Perhaps the most incredible thing about these cleaning stations is the fact that there are many different species of both cleaned fish and cleaner fish/shrimp in these cleaning lines, but they somehow manage to communicate and get through the cleaning. This communication between species is evidence that some chemical exchange must be occurring.
Starfish
True starfish (not to be confused with brittle stars) are part of the Echinoderm class Asteroidea. They are all marine, and have pentaradial symmetry—meaning five-sided radial. Most starfish have five arms, but these arms “split” in some species, resulting in more arms (but always in a multiple of five.) These arms have no set length—they can even be merely stubs, like in the pillow (or cushion) star. Asteroids have a Water Vascular System, which they pump full with sea water through a bony pore called a madreporite (white spot seen in picture) on their aboral surface (top surface). They use their WVS for locomotion, food and waste transportation, and even respiration.
Starfish are incredible creatures. They have no eyes, ears, or nose—but they get by using extraordinarily sensible elongated sucker-like muscles, or tube feet, that line their arms; some tube feet even have simple light receptors that act as primitive eyes. They can regenerate an arm (or two or three) if lost. This can be considered a form of asexual reproduction. They are predators, and can regurgitate their “stomach” and surround/digest their prey (usually clams and other brachiopods.)
