An integrated series of structural studies on the frog, xenopus and bovine retinal rod outer segment (ROS) is proposed. Studies include 1) determination of the z-projection of frog rhodopsin from 2-dimensional sheets (space group P22121; unit cell 47 A x 151 A), using glucose and auro-thio-glucose; 2) determination of factors controlling hexagonal and lamellar phases of ROS lipids; and 3) determination of potential form components contributing to the birefringence banding in Xenopus photoreceptors.