Today was a wonderful day. We visited Gardner Bay on Española Island where we indulged in our snorkeling activities. Some of us experienced the glass bottom boat. During this activity, we had the opportunity to see lots of different tropical fish and sea urchins attached to the bottom of the ocean. Anyone who has watched a hatpin urchin moving slowly along the bottom can have little doubt about the protective function of the long, sharp spines. The spines are in constant motion, even a passing shadow causes the urchin to turn more spines in that direction. Other sea urchins have less formidable spines than the hatpin urchin, but all bear the spiny armament suggesting echinos, the Greek word for hedgehog, from which the echinoids get their scientific name. Sea urchins move along the bottom or on rock faces by their slender tube feet, which also serve as feelers to detect changes in their surroundings. Many urchins also walk along on their spines.
Approximately 900 species of echinoids have been described, and are widely distributed in all seas, from the intertidal to deep sea. Thirty- seven species of echinos have been recorded from the Galapagos Islands.
