Aufwuchs Protozoa and Bacteria on the Gills of the Rock Crab, Cancer irroratus Say: A Survey by Light and Electron Microscopy1

Abstract
Histological examination of gills of the rock crab (Cancer irroratus Say, 1917) taken from specimens collected in polluted and nonpolluted areas indicated that gill discoloration was not directly related to the degree of microbial fouling. Light microscope studies demonstrated that bacteria, peritrich and suctorian ciliates, and some naviculoid diatoms were the principal members of the fouling community. Examination of the bacteria by electron microscopy showed that several distinct types were present, and that some of these were attached to the gill by holdfast structures while others were enmeshed in a filamentous slime layer. An unusual small marine flagellate and an unidentified amoeba were also examined ultrastructurally.