Embryo to Hatching Out:

Drop your spare change here... make a donation to help with conservation!

Embryo Development

An estimated 90,000 eggs, measuring between 3 mm and 3.7 mm, are laid in one season by one female. The outer chorion of the eggs remain sticky for about 15 hours and is responsible for the egg eventually becoming totally covered with sperm.

A complex sequence of surface events in the egg begins after fertilization. These include several granulations of the egg and the eventual production of an expandable, inner egg membrane, which subsequently ruptures the chorion and serves as a larger enclosure for the developing embryo.

By the fourth day after fertilization, rudimentary appendages can be seen in the egg. Three embryonic moltings later (by the 8th day), the legs and book gills are visible. The horseshoe juveniles "hatch out" by the 14th day and begin the cycle of growth and molting that will continue until they reach their adult size 10-11 years later.