I20 I N A G U A 



until I had watched them for a long time from the sanctuary 

 of my bath. One of the things that always astonished me was the 

 immaculate appearance of their bodies. Although the surf at 

 times piled loose carpets of torn seaweed over the boulders and 

 cast up gritty piles of loose gravel and coarse sand, and although 

 all the other animals, the snails, mussels and chitons, had a 

 rubbed worn look, or were covered with parasitic barnacles, 

 the sea urchins were always spotless; no grains of sand, strands 

 of algae or blotches of parasites marred their jet black coats. 

 This was particularly remarkable when one considered that 

 their spines should have been catch-alls for all manner of debris. 

 They had a very clever system of keeping themselves clean. 

 When a fragment of sand or dirt fell between the needles, it 

 was grasped by a tiny clamp or pincers equipped with a triple 

 set of jaws, like those of certain types of dredges; these wxre 

 mounted on a flexible shaft of muscle and skin which trans- 

 ported the debris to the next claw which carried it to another, 

 or to one of the tube feet which were also scattered over por- 

 tions of the creature's upper surface, and so on until the offend- 

 ing fragment was dropped into the water. Small parasites that 

 sHpped between the barrier of spines were not treated so gently. 

 The moment they touched the urchin's side the claws began 

 snapping, opening and shutting until they seized on some por- 

 tion of the animal's anatomy. Once a pincers secured a grip it 

 held on tenaciously and then if a struggle ensued, other claws 

 came to its rescue until the captive was held rigid by myriads 

 of tiny clamps. Only death of the parasite caused the grip to be 

 relaxed; the corpse was then passed from claw to claw, foot to 

 foot until it reached the urchin's mouth and was devoured. 



The hundreds of tube feet were not the only method these 

 animal cacti utilized in retaining their position in life. Great 

 numbers of them lived in cavities in the rocks; their bodies were 



