The pallial glands and rock boring in Lithophaga lithophaga (Lamellibranchia, Mytilidae)

The secretion of the pallial glands is generally held responsible for rock boring in Lithophaga lithophaga (L.). The glands do not secrete acid; the pH of the secretion was found to be about 6.5. Histochemical tests showed that the secretion is a neutral mucoprotein with calcium-binding ability. This finding indicates, that complexing of calcium by the secretion of the pallial glands is the mechanism of chemical boring into calcareous rock in L. lithophaga.