Optical fibers in sponges?

Grantia is a genus of calcareous sponges belonging to the family Grantiidae. Grantias contain spicules and spongin fibers. Spicules are structural elements found in most sponges. They provide structural support and deter predators. Large spicules, visible to the naked eye are referred to

Too many mouths?

Stomata, are the mouths of plants. Plants breathe through them, just as we do with our lungs. They are not visible to the naked eye, and a plant therefore needs quite a lot of them. However, there must be

Hair? Where?

True hair is found only in the Class Mammalia, and there is really no such thing as an absolutely hairless mammal. Even whales (at least some of them) have rudimentary hairs here and there. Some other animals have hair-like structures, but if you have real hair, you're a mammal.

Hair serves many functions. The most obvious is to serve as insulation, but it's also used to provide camouflage (for example, the spot pattern