Cynomolgus and Rhesus Monkey Visual Figments

Microspectrophotometric measurements were performedon 217 photoreceptors from cynom*us, Macacafascicularis, and rhesus, M. mulatto, monkeys. The distributions of cell types, for rods and blue, green, and red cones were : 52, 12, 47, and 44, respectively, for the cynomolgus, and 22, 4, 13, and 13 for the rhesus. Visual cells were obtairled fresh (unfixed), mounted in various media (some containing 11-cis-retinal), and then located visually under dim real (650 nm) illumination . Absolute absorbance (A), linear dichroism (LD), andbleaching difference (BD) absorbance spectra were recorded through the sides of outer segments . The spectra were suljected to rigorous selection criteria, followed by digital averagingandFourierti-#nsform filtering . Statistical methods were also applied to the accepted samples in the estimation of population means and variances. The wavelength of mean peak absorbance (nm,x) and the standard error at 95% certainty of the rod and blue, green, and red cone pigments in cynomolgus were 499.7 t 2.5, 431 .4 t 4.2, 533.9 t 2.4, axtd 565.9 + 2.8 nm, respectively . The rhesus pigments were statistically indistinguish4ble from the cynomolgus, having Xmax of -500, 431, 534, and 566 AM . Statistical tests did not reveal the presence of a Xmax subpopulation (i .e ., anomalops pigments). The bandwidth of each a-band was determined in two segments, giving rise to the longwave half-density (LWHDBW), shortwave halfdensity (SWHDBW), and total half-density (THDBW) bandwidths. The LWHDBW was found tq have the smallest variance. Both the LWHDBW and the THDBW showed linear dependence on the peak wavenumber (a ,aX )-t for the four macaque pigments.