THE PUPIL RESPONSE OF A TELEOST FISH, PORICHTHYS NOTATUS - DESCRIPTION AND COMPARISON TO OTHER SPECIES

The pupil response of Porichthys notatus to different intensities of i llumination is described and compared to that of P. myriaster, Cephalo scyllium ventriosum, and a human. While the fully dark adapted pupil i s round, at the highest light intensities it consists of only two smal l, almost independent, apertures with a total area 4.9% of that observ ed in the fully dilated animal. The response is at least partially con sensual and occurs, albeit at a much reduced rate, in isolated eyes. P . notatus also displays retinomotor movements comparable to those seen in most teleosts, suggesting that, contrary to most previous assumpti ons, pupillary responses and retinomotor migrations are not mutually e xclusive. (C) 1998 Elsevier Science Ltd. All rights reserved.