The water is expelled through the shark's five pairs of gill slits. (ixchelbeachhotel.com)
What the anti-choicers don't tell you is that those embryos are tiny, bean - sized growths that have gill slits left over from our fish ancestors and tails left over from our primitive mammalian ancestors. (religion.blogs.cnn.com)
Human fetuses, for example, show temporary gill slits and tails during development. (discovermagazine.com)