Embryo Development
During the embryonic development stage, the horseshoe crabs are quite active. The movie to the right was filmed approximately 10 days after insemination. Notice that the legs appear well-formed and functional.
The embryo shown here will hatch out in about 4 days. After hatching, the juvenile won't begin eating until after its first molt, which occurs within the first week to ten days. The tail is also not fully articulated (moveable) until after this initial molt. The juvenile will molt another four to five times within the first year, but will still be quite small, as shown below.