Figure 9A. Position of oil droplets in photoreceptors. These drawings represent some of the diversity of reptilian photoreceptor anatomy. The orientation of these cells is such that the outer segments are at the top, and light from the lens would enter from the bottom. The "d's" show the positions of oil droplets in the photoreceptors which have them. The "p's" indicate which receptors are paired (see text and Figure 11). Oil droplets are situated immediately prior to the light-sensitive outer segments in the photoreceptors that have such droplets. They thus act as a screen of the light prior to its absorption by these photoreceptors. (Adapted from Walls 1942). See Figure 9B, Figure 9C.