Innervation of the conus papillaris in the eye of lacertilians.

The autonomic innervation of the conus papillaris has been observed by electron microscopy in Lacerta viridis, muralis, Anguis fragilis and Zonosaurus ornatus. Bundles of nerve fibres accompanying blood vessels penetrate the conus at the level of the intraocular portion of the optic nerve. Within the conus proper, different aspects are described: bundles of fibres from which some axons can be separated, aggregates of axons with varicosities enclosed within the cytoplasm of pigmented cells, isolated preterminal axons or varicose terminals encircled by pigment cell cytoplasm or cytoplasmic processes, and naked terminals. The observed innervation is to be related to blood vessel vasomotor activity or to pigment cell motility. This problem remains unsolved.