The glass octopus (above), also known as Vitreledonella richardi, is a transparent, gelatinous, and almost colorless octopod found worldwide in tropical and subtropical seas. Eyes are nearly rectangular in shape as seen from the side. The radula is heterodont, also known as heteroglossan, in which the middle or rhachidian tooth is each array has multiple cusps and the lateral teeth are unicuspid. The female broods her eggs, of which there are hundreds, within the mantle cavity. Continue reading for more translucent animals.