The pluteus larvae of the sand dollar Dendraster excentricus and their diel vertical distribution have been well studied in the field and in lab. However, there has not been much focus on how the larvae and their vertical distribution change as a response to entrainment by an incandescent light source. In order to test this, two groups of the D. excentricus plutei were set to different day/night cycles, one receiving 12 hours of light, the other receiving only 5 hours. The swimming patterns and growth of these two treatments were observed and compared. The results indicated that the larvae could be entrained to incandescent light as vertical distribution and growth varied between the two treatments.