CYTOCHEMICAL DEMONSTRATION OF ACID-MUCOPOLYSACCHARIDES IN THE EPICUTICULAR SURFACE-COAT OF THE CRAB CARCINUS-MAENAS (L) (CRUSTACEA, DECAPODA)

The epicuticle of marine decapod crustaceans is composed of three subl ayers : the inner epicuticle, the cuticulin layer, and the surface coa t which was previously described as an external layer rich in tannophi lic proteins. Positive staining by ruthenium red and alcian blue sugge sts the presence in this layer of polyanionic sites and acid mucopolys accharides. The surface coat might be viewed as a hydrophilic glycopro teinaceous layer reducing the surface tension between the hydrophobic cuticulin layer and the aqueous environment.