Structural elements of the gills of the shore crab Carcinus mediterraneus

Fine structural studies were conducted on the gills of the shore crabCarcinus mediterraneus using scanning electron microscopic techniques. The results obtained show the structural organization of crab gills from whole gills including spiny elements over the 150 lamellae to lamellar components such as cuticles, median shaft, marginal canal, afferent and efferent lamellar vessels and hemolymph cells. Enormous surface enlargement is accomplished by a variety of structural elements which allow rapid circulation of hemolymph. In the form of a relatively small organ, the gills fulfill all the necessary exchanges of specific molecules between the crab and its environment. Aggregations of ca 1-μm particles covering the outer cuticular surfaces are considered to be bacterial colonies of unknown properties and functions.