If it’s lucky, Adelomelon brasiliana spends its life in coastal waters of Brazil, Uruguay, and Argentina, half-swallowed by sand. There, the snail, whose tawny or ashen shell measures more than seven inches long, mates and eats. Scientists don’t know a ton about its diet, but its brethren—other gastropods in the family Volutidae—are carnivorous. What’s certain is that during breeding season, pearly orbs drift through its neighborhood. Unlike species that deposit their eggs somewhere sturdy, like on a rock, A. brasiliana sets its egg capsules free. The milky or translucent spheres,…
