Why are some animals translucent? And how exactly does biological transparency work?

Transparency is an intriguing physical trait found throughout the animal kingdom, and in oceanic species, especially; as pointed out in this excellent overview of transparent animals by Scientific American's Sönke Johnsen, "almost all open ocean animals not otherwise protected by teeth, toxins, speed or small size… »9/18/12 6:40pm9/18/12 6:40pm