This appears to be the same as the animal figured as Berghia salaamica on Sea Slugs of Hawaii, although it is very similar to B. major.. There is still disagreement among the experts about whether this belongs in Berghia or Spurilla. This specimen was found under a rock on the reef at Kewalo Basin at a depth of about .5m.
Links:
Sea
Slugs of Hawaii
Created 20 April 2009