A 3D model of two joined serial tomograms of a monkey rod OS. The movie shows the plasma membrane modeled in green and the mature disks modeled in dark blue. The plasma membrane includes the ciliary plasma membrane, the membrane enclosing the mature disks, and the nascent disks, which are mostly lamellae, open to the extracellular space. The 3D model rotates and then zooms in on a bilobed invagination at the OS base (Fig. 3 A–E). Fig. 2D is from the same 3D model, except that it is depicted with only unidirectional lighting. The 3D model is based on segmentation of the two tomograms at the end of the sequence shown in Movie S3. The movie was created with Chimera.