SPECTRAL SENSITIVITY AND PHOTOTAXIS IN THE OPOSSSUM SHRIMP, NEOMYSIS AMERICANA SMITH

¹ Narragansett Marine Laboratory, University of Rhode Island, Kingston, Rhode Island

1. Laboratory experiments were conducted to determine the spectral sensitivity of N. americana. The intensity of light beams passing through four Corning glass color filters was made equal with Wratten neutral density filters.

2. The positively phototactic animals showed a definite preference for light passing through a color filter having peak transmission at 515 mµ.

3. Increasing the intensity of light passing through the three other color filters did not alter the mysid preference for the wave-length 515 mµ.

4. Phototactic experiments revealed that N. americana was photopositive unless subjected to total darkness for 12 hours; after longer periods in the dark they were photonegative.

5. Experiments indicate that it is not likely that the photic response in N. americana is governed by a biological time clock.