National Geographic : 1981 Aug
Ingenious security blanket, the egg capsule of the Japaneseswell shark is a marvel of protective design. The palm size capsules come with strings attached, which are wound around strands of coral (left), here 165 feet deep in Japanesewaters. Hidden from predatorsand secure againstbuffeting currents, the embryo within (right) about three months old and with tiny developing pectoralfins-feeds from its yolk sac. After about a year the capsule splits, and a newborn swell shark (below) leaves the nursery to hunt crustaceansand mollusks. As an adult, it will grow to about 3.5 feet in length.