Figure 12. Double cone mosaic. When viewed as a whole mount looking through the retina in the direction light would normally travel in an intact eye, double cones can be seen to form regular patterns in some animals, particularly teleosts. This image is of fixed and stained tissue from a green sunfish (Lepomis cyanellus) focused at the level of the inner segments. The mosaic is typically described as "square" because the long axes of double cones are arranged like the sides of squares around a central single cone, although careful analyses of sunfish retinas suggest that the mosaic might more accurately be described as rhombic (Cameron and Easter 1993). Clicking on the image will cause a square and a pair of dashed lines to appear as highlights of the regularity of this particular mosaic. (Photo prepared by D.A. Cameron and S.S. Easter, Jr.)