a1 Department of Psychology
a2 University of California, Santa Barbara
Ungulates have been classified as having arrhythmic eyes in the sense that they contain features appropriate both to diurnal and nocturnal life. The former is typically associated with multiple classes of cones and a color-vision capacity. To see if an arrhythmic animal has these features, the number of cone classes was determined and the spectra of these cones were measured in a common ungulate, the domestic pig (Sus scrofa). Examination with electroretinogram (ERG) flicker photometry revealed the presence of two classes of cones in the pig's eye having average maximum sensitivity (λmax) at 439 nm and 556 nm, respectively. This ungulate thus has the requisite retinal basis for dichromatic color vision.
(Received April 14 1988)
(Accepted June 28 1988)
Reprint requests to: Jay Neitz, Department of Psychology, University of California, Santa Barbara, CA 93106, USA.