Reaching the reef, he turned north and headed into deeper water, keeping the rocks on his right-hand side. He kept his eyes trained on the changing terrain, alert for signs of his intended quarry. Ever watchful, he passed disinterestedly over the rockfish and sculpins that followed him with cautious eyes, although he paused briefly to observe a rose anemone devouring an unfortunate jelly that had drifted into its stinging grip. It was a routine act of underwater survival, yet the simple act of feeding was turned, somehow, into performance. The jelly’s ravaged and impotent tentacles swirled around the anemone’s translucent arms, each one tipped with the deepest pink, as they danced a brutal ballet. Dulled by poison, the jelly fluttered like a failing heart as it was pulled, inexorably, into what passed for the anemone’s mouth.

At thirty-seven feet he spied a flash of yellow amidst the purple and black of the rocks, and stopped. Maintaining his position in the water column, he hovered almost motionlessly as he gazed upon the tiny creature before him. Less than three inches long, it resembled nothing so much as a slice of lemon peel, a scrap perhaps tossed over the side of a boat, a bit of refuse that had drifted down to settle, randomly, on the rock below. Closer up, however, it revealed itself to be something far more interesting than a bit of rind. Its surface was covered with hundreds of tiny bumps, and a line of black spots formed a trail that originated between two cone-shaped appendages on the animal’s head and ran the length of its back, where it ended in a seven-branched spray of fernlike plumes.

As Ben observed his find, he thought, not without irritation, that its common designation—sea slug—did no justice whatsoever to the marvelousness of its design. The slug, moving nearly imperceptibly over the surface of the reef, presumably cared little about its name, but Ben was offended for it. He preferred its more noble, and accurate, classification of nudibranch, and liked even more its full proper name of Archidoris montereyenis, the Monterey dorid. He considered it the local representative of its genus, native to their very own Monterey Bay and therefore deserving of celebrity status.

The nudibranch, with admirable focus, was feeding. Although its outward appearance suggested a complete lack of activity, Ben knew that on its underside its ribbon of cartilaginous teeth was scraping away at the encrusting marine sponges that dotted the surface of the rock. From time to time, it revealed itself to be engaged by the furling and unfurling of its delicate branchial plume, like a flower blooming over and over again.

The creature was perfect in its design, which is why he had fallen in love with it, and with all its kind, upon their first meeting. Common to all of the world’s oceans, the nudibranchs nonetheless remained objects of mystery. Although they were frequently photographed due to their uncommon beauty and their habit of remaining for a long time in one spot, making them excellent subjects, their lives were largely unrecorded. It was suspected that they contained within themselves numerous compounds with medical applications, only a few of which were even in the beginning stages of study. It was to unlocking their mysteries that Ben had devoted his life.