Fig. 10

Two of the several paths of eye evolution followed in mollusks. Contrary to some representations of the eyes in Fig. 9, there is no simple linear series from eye patch to complex camera type eye. Rather, eyes may evolve in a variety of ways, becoming specialized as pinhole-type, lens-type, or other types of eyes from an early beginning. These are examples of eyes from modern species, and not actual ancestor–descendant transitions. Note that these images are not drawn to the same scale (Nautilus eyes are about 10 mm across whereas the others are about 1 mm). From Land and Nilsson (2002), based on drawings by Hesse (1908; Patella, Haliotis, and Helix), Young (1964; Nautilus), and Newell (1965; Littorina), reproduced by permission of Oxford University Press and Blackwell