Fig. 4. Immunohistology of C. magister. Tissues oriented with external surface of crab on right; counterstained with hematoxylin. (A) Late premolt crab incubated with C. magister anti-cryptocyanin monoclonal antibody shows cryptocyanin staining brown in subepidermal connective tissue (ct), elongated epidermal cells (e) and newly secreted exocuticular layer (ex). Reserve cells (rc), old exocuticle (oex), old endocuticle (oen). (B) 18 h postmolt crab shows immunoreactivity to cryptocyanin in new endocuticle. Circle indicates area enlarged in C. (C) Area of new exoskeleton enlarged 10x from B. Newly formed endocuticle (en) is immunoreactive to cryptocyanin; new exocuticle (ex) is now immunonegative. Scale bar: A=70 µm; B=100 µm; C=10 µm.