1. Photoreceptor Evolution: Ancient ‘Cones’ Turn Out to Be Rods
Eric J. Warrant 
Current Biology 
Volume 25, Issue 4, Pages R148-R151 (February 2015)
DOI: /j.cub
Copyright © 2015 Elsevier Ltd Terms and Conditions

2. Figure 1 The sea lamprey Petromyzon marinus.
(A) The gills slits and well developed eyes. (B) The mouth with its concentric rows of horny teeth. Images used with kind permission of the photographers: A. Muir (A) and T. Lawrence (B) of the Great Lakes Fishery Commission, USA.
Current Biology  , R148-R151DOI: ( /j.cub )
Copyright © 2015 Elsevier Ltd Terms and Conditions

3. Figure 2
The morphology of rods (left) and cones (right) in modern jawed vertebrates.
Note the outer segment lamellae (L) and internalised cytosolic disks (D) characteristic of cones and rods, respectively. After [12].
Current Biology  , R148-R151DOI: ( /j.cub )
Copyright © 2015 Elsevier Ltd Terms and Conditions