the rolling billows.  The wall of the reef opposed to the sea was a rough slope from the summit to the bottom, buttressed against the attacks of storms, and defended by chevaux-de-frise such as the Americans sank in the Hudson River in 1777.  I ventured cautiously over the edge.  A student of ancient tactics would have found there all the old defenses in coral—­caltrops, and abatis, molded in dark-gray coral, battered and shot-marked.  It was a dream of a sunken city wall of old Syracuse, and conjured up a vision of the hoary Archimedes upon it before the inundation, directing the destruction, by his burning-glass, of the enemy’s ships.  The side of the reef toward the land was as sheer as an engineer could make it with a plumb-line.  The coral animals had as accurate a measure of the vertical as of defense against the ocean.

Over this levee rolled or slid a dozen kinds of shellfish spying out refuges against the breakers and their brother enemies in the troughs and holes of the coral floor.  With my small spears I pried out dozens of them, Mao, starfish, clams, oysters, furbelowed clams, sea-urchins, and sponges.  The mao is the turbo, the queer gastropod sold in the market in Papeete.  He lives in a beautiful spiral shell, and has attached to him a round piece of polished shell, blue, green, brown, or yellow, which he puts aside when he wishes to feed on the morsels passing his door, and pulls shut when he wants privacy.  He fits himself tightly into a hollow in the reef and dozes away the hours behind his shield, but ready to open it instantly at the perception of his favorite food.  The mao was wedged in the recess so cleverly that it was difficult to extract him by my hand alone.  His portal I kept after eating him raw or cooked, to have set in silver as an exquisite souvenir of my visit.  These jewels studded the drinking cups from which the Vikings drank “Skoal to the Northland!”

The starfish were magnificent, of many colors, and one with fifteen arms covered with sharp, gray spines, and underneath pale yellow, fleshy feelers with suckers like a sea-anemone.  These were as pliant as rubber in the water, but, when long out, as hard as stone.  The sea-urchins were of many kinds, some with large spikes, as firm as rock, and others almost as brittle as glass, their needles, half a dozen inches long and sharp, dangerous to step on even with my rubber-soled, canvas shoes.  All hues were these urchins, blood-red and heavenly blue, almost black, and as white as snow, the last with a double-star etched upon his shell.  Others were round like blow-fish, with their spickles at every angle, menacing in look.

The clams and oysters were small, except the furbelowed clam, whose shell is fluted, and who grows to an immense size in the atolls of the Paumotus.  I always ate my fill of these delicacies raw as I walked along the reef, smashing the shells to get at the inmates.