QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by HUGHES, H. P. I. Search for Related Content PubMed Articles by HUGHES, H. P. I.

Journal of Experimental Biology 52,609-618 (1970)
Published by Company of Biologists 1970

The Spectral Sensitivity and Absolute Threshold of Onchidoris Fusca (MÜller)

HELEN P. I. HUGHES ¹

¹ Marine Science Laboratories, Menai Bridge, Anglesey, North Wales, U.K.; Biology Department, Dalhousie University, Halifax, Nova Scotia, Canada.

1. The response of Onchidoris fusca to monochromatic light in the range 400-650 mµ was measured in behaviour experiments with two opposing lights.

2. The peak sensitivity was found to lie at 500-505 mµ. The thick, brown, dorsal skin of Onchidoris has the effect of reducing the sensitivity of the eye to ultraviolet and blue light.

3. After allowing for a 90% absorption of light by the dorsal skin, the absolute threshold of the naked eye of Onchidoris (at 501 mµ) was found to lie between 81 and 106 quanta/sec./eye.

4. If the lens and cornea absorb a further 10% of the available light, then each of five receptor cells in the eye of Onchidoris may be capable of responding to 12-18 quanta/sec. However, the effective threshold of the eye of Onchidoris is much higher, lying at 881-1148 quanta/sec.