. 2012 Sep 6;7(9):e44257. doi: 10.1371/journal.pone.0044257

Table 1. Short-wavelength (S), Medium-wavelength (M), Long-wavelength (L), cones per square millimeter (c/mm²).

	Chick	Ground Squirrel	Human
Cone Vision	Tetrachromatic-S-M2-M1-L	Dichromatic-S-M	Trichromatic-S-M-L
Oil Droplet	Yes	No	No
High Acuity Vision	Area Centralis	Visual Streak	Fovea Centralis
Fovea	No	No	Yes
Average Retinal Cone density	10,000–35,961c/mm² (a)	24,310–49,550c/mm² (b)	2500c/mm² peripheral 6000c/mm² central (c)

^a.

Reviewed in [52]. Cone density varied widely between experiments.

^b.

Peak cone density was highest in the visual streak and lowest density in the dorso-nasal periphery [51].

^c.

Determined by histology from donor eyes [72].

Table 1. Short-wavelength (S), Medium-wavelength (M), Long-wavelength (L), cones per square millimeter (c/mm2).