Sea urchins, including the two that carry venom and the two that live buried. Several of them are the reason a diver looks at where a hand is going.
The hosts come first. The fire urchin carries Coleman shrimp and zebra crabs, and the long-spined urchin is a moving thicket that a good number of small animals live inside. A fair share of the shrimp and crab entries in this index are found by searching an urchin.
The hazards are real and limited. The flower urchin's venom is in the flower-like pedicellariae rather than in the spines, and the fire urchin carries venom sacs below the spine tips. The long-spined urchins puncture rather than envenom, and on the banded urchin it is the short dark spines that do the damage, not the long blunt ones.
The heart urchin and the sand dollar live under the sand and are known from the trace they leave more often than from the animal.
Every one has a page. They are shown as a list rather than as pictures because nothing has been photographed or logged for them yet, and a species with nothing behind it should not sit in front of one that has.
How many of the 23 carry a record at each destination. A species usually carries several, so these do not add up to 23.
All 1316 species in one index, with filters for destination, rarity and hazard.
