Helmet urchin
The tidal pools in front of our (rented) condo held hundreds of these little creatures.
The largest were about the size of half a golf ball (approximately 1.75 inches [44 mm]),
although I understand they can be found in larger sizes.
They cling tenaciously to the lava rock despite vigorous wave action.
We learned what they were called, as well as some other facts about them,
while having breakfast on our lanai. You gotta love the "interweb".
Please login or register.