title: The pupillary response of cephalopods.
abstract: This paper provides the first detailed description of the time courses of light-evoked pupillary constriction for two species of cephalopods, Sepia officinalis (a cuttlefish) and Eledone cirrhosa (an octopus). The responses are much faster than hitherto reported, full contraction in Sepia taking less than 1 s, indicating it is among the most rapid pupillary responses in the animal kingdom. We also describe the dependence of the degree of pupil constriction on the level of ambient illumination and show considerable variability between animals. Furthermore, both Sepia and Eledone lack a consensual light-evoked pupil response. Pupil dilation following darkness in Sepia is shown to be very variable, often occurring within a second but at other times taking considerably longer. This may be the result of extensive light-independent variations in pupil diameter in low levels of illumination.
authors.affiliation: The Henry Wellcome Laboratories for Vision Sciences, Department of Optometry and Visual Science, City University, Northampton Square, London EC1V 0HB, UK. r.h.douglas@city.ac.uk
authors.forename: R H
authors.initials: RH
authors.lastname: Douglas
authors.forename: R
authors.initials: R
authors.lastname: Williamson
authors.forename: H-J
authors.initials: HJ
authors.lastname: Wagner
mesh_terms: D000818:Animals; D001267:Atlantic Ocean; D008027:Light; D008974:Mollusca / Q000502:physiology*; D012025:Reflex, Pupillary / Q000502:physiology*; D013045:Species Specificity; D013997:Time Factors