Transparent Squid

Found on the southern hemisphere's oceans, the Glass Squid (Teuthowenia pellucida) has light organs on its eyes and possesses the ability to roll into a ball, like an aquatic hedgehog. It is prey of many deep-sea fish (eg goblin sharks) as well as whales and oceanic seabirds. (Photo by Peter Batson)

Transparent Jellyfish

Jellyfish are free-swimming members of the phylum Cnidaria. They are found in every ocean, from the surface to the deep sea. Many jellies are so transparent that they are almost impossible to see. The one above is from the Arctapodema genus, with a size of an inch-long (2.5-centimeter-long). (Photo by Bill Curtsinger)

Transparent Amphipod

Called Phronima, this unusual animal is one of the many strange species recently found on an expedition to a deep-sea mountain range in the North Atlantic. In an ironic strategy for survival, this tiny shrimplike creature shows everything it has, inside and out, in an attempt to disappear. Many other small deep-sea creatures are transparent as well, or nearly so, to better camouflage themselves in their murky surroundings, scientists say. (Photo by David Shale)

Transparent Head Fish

This bizarre deep-water fish called the Barreleye (Macropinna microstoma) has a transparent head and tubular eyes. It has extremely light-sensitive eyes that can rotate within his transparent, fluid-filled shield on its head, while the fish's tubular eyes, well inside the head, are capped by bright green lenses.

The eyes point upward (as shown here) when the fish is looking for food overhead. They point forward when the fish is feeding. The two spots above the fish's mouth are not eyes: those are olfactory organs called nares, which are analogous to human nostrils. (Photo by MBARI)

Transparent Frog

Native to Venezuela, the Glass Frogs belong to the amphibian family Centrolenidae (order Anura). While the general background coloration of most glass frogs is primarily lime green, the abdominal skin of some members of this family is transparent, so that the heart, liver, and digestive tract are visible through their translucent skin. (Photo by Heidi and Hans-Jurgen Koch)