Reproduction in the Giant Isopod, Bathynomus giganteus

Summary

Aspects of the reproductive biology of the giant isopod, Bathynomus giganteus (Edwards) resemble those of other isopods. In females, the gonopores are located on the sternal midline of the eighth thoracic somite and the eggs are brooded in a marsupium. The reproductive tract of the males also resembles those of other isopods. The paired vasa deferentia open into two penes located on the sternal midline of the eighth thoracic somite. The vasa deferentia are formed of columnar epithelial cells with basal nuclei. The lumen is filled with seminal products consisting of aggregrates of spermatozoa surrounded by extracellular tubules. The sperm head consists of an acrosome and subacrosomal rod from which a pendant nucleus extends. The tails are composed of an amorphous core consisting of a dark band, two medium bands, two light bands followed by a dark band again. The tails are attached to the heads by a knob which is an extension of the core