Slipper lobsters have paddle-shaped antennae and are typically found on cavern ceilings during the day.  Large species are no longer common due to heavy fishing pressure and disregard for local laws.  Minimum tail width is 2.75 inches.  Illegal to harvest from May through August, spearing and taking of females with eggs prohibited.

http://hawaii.gov/dlnr/dar/regulated_fish_mia.html

Haleiwa Trench, Oahu, 25 feet

Locally common at night among ledges and caverns at scuba depth.  Attains 7 inches.  Hawaii, New Caledonia, Easter Island, and Reunion.