In tens, please (ten pound notes)
asacol hd price The chapter on barrel sponges is a discussion of symmetry, some of the oldest living creatures on Earth and, crucially, what it actually means to be an animal. "We may know that, strictly speaking, they are animals but their lack of eyes, mouths, organs and the power of movement means that they don't really feel like animals," Henderson writes about the barrel sponges, a bunch of tube-like creatures that are often big enough to surround a person should they want to swim inside. Like the previous chapter, we start with a brief description of a fantastical animal and we quickly jump to another place entirely ??? a gripping story of evolution that leaves us to ponder on the concept of "deep time", the billions of years that life on Earth has evolved and of which humans are the merest fraction of a part. As Henderson puts it: "Human history with respect to life on Earth is as deep as the displacement of the smallest seabird floating on top of a wave over the deepest part of the ocean."