Basic Information on the Jewel Urchin- Lytechinus williamsi
The body of the jewel urchin is round in its outline but is covered with short spines. The spines part somewhat to form apparent grooves along the major plates. A red line is visible where the plates meet. The lower half of a sea urchin's body is referred to as the oral surface, because it contains the mouth, while the upper half is the aboral surface. The internal organs are enclosed in a hard test or shell composed of fused plates of calcium carbonate covered by a thin dermis and epidermis. The plates are covered in rounded tubercles, to which the spines are attached. The color of the animal is usually light to white, but may be variable. The spines are colored uniformly, but range in color from green to white. Between the spines, the purple podia are large and prominent. It inhabits the reef and hides during the day and feeds during the day. It is common all over the Caribbean.
The Nervous System of The Jewel Urchin - LYTECHINUS WILLIAMSI
Sea urchins have been researched by scientists and they have discovered that urchins can live for over 200 years. They have discovered that sea urchins have light sensitive cells at the ends of their spines that cover the rest of their body. They have no brain and the neural center is a large nerve ring encircling the mouth just inside the lantern. From the nerve ring, five nerves radiate underneath the radial canals of the water vascular system, and branch into numerous finer nerves to innervate the tube feet and spines.