Fig. 7. Immunocytochemical localization of Ha-CalpM in claw muscles from adult lobster. Transverse sections were stained with Hematoxylin/Eosin (B) or incubated with pre-immune serum (A) or Ha-CalpM antiserum (C,D). Nuclei (arrowheads) are associated with the sub-sarcolemmal cytoplasm of sarcolemal clefts (arrows), which are large infoldings of the cell membrane. The Ha-CalpM antiserum stained the cytoplasm uniformly and some nuclei. Each field of view contains portions of two muscle fibers. ES, extracellular space. Scale bar, 100 µm.