The objectives of this project are six fold: 1. To analyze the structure of retinal receptor outer segments of the frog retina. In particular, the objective is to develop procedures employing electron microscopy and immunohistochemistry which will serve to localize functional subunits (visual pigments) within the membranes of outer segments. Peroxidase labeled antibodies will be used to study the distribution of membrane antigens along the surface of these biological membranes by negative staining and thin-section technique for electron microscopy. 2. To localize by immunohistochemistry rhodopsin within the iris of the frog eye. 3. To develop methods for the isolation of sarcolemma from frog cardiac muscle. Identification of the membrane preparation will be done by analysis for enzymic markers and immunohistochemical procedures employing the peroxidase labeled antibody. Finally, a chemical analysis of the proteins and lipids of the membrane preparation will be performed. 4. To analyze by electron microscopy the structure of the garfish olfactory nerve to determine the ratio of axon membrane to Schwann cell membrane. Further to characterize ultracentrifugal pellets of garfish olfactory nerve for biochemical and x-ray diffraction studies. 5. To analyze the structural changes of paramyosin- containing thick filaments in sarcomeres of Limulus striated muscle during shortening. Light diffraction techniques coupled with electron microscopy will be used. 6. To analyze structural changes in paramyosin-containing thick filaments in Mytilus ABRM during "catch".