Histological response to injury in the horseshoe crab, Limulus polyphemus

Abstract

Observations are presented on the wound repair process of the horseshoe crab, Limulus polyphemus. A cut, 1 × 40 × 3 mm, was made through the dorsal abdominal carapace and observations of the tissue at the wound site were made at 6, 24, 48, 96 h and 5, 10, 15, 30, 60, 90, 120, and 180 days. The wound was immediately plugged by a hemolymph coagulum and there was heavy infiltration of hemocytes into the area. Infiltrating hemocytes undergo a series of changes. The outermost cells hyalinize and form a thick layer between the cut ends of the exoskeleton. Pigmented epithelial cells migrate into the scar and produce a layer of cuticle under the cut exoskeleton. During the remaining period of observation, the cuticular scab enlarged and the cellular mass that filled the wound channel was lost through a series of changes that eventually restored the original tissue structure.