Ratfish
Perhaps the best-known species is the Spotted Ratfish (Hydrolagus colliei) of the west coast of North America. Females of this species produce only two eggs at a time, packaged in capsules that resemble tiny violin-cases. The eggs require what must be an unpleasantly long time to extrude and may trail behind a female for 4 to 6 days before dropping off. The Spotted Ratfish is frequently encountered at night by scuba divers off Washington and British Columbia. At night, this ratfish flaps over expansive plains of fine mud in water 20 to 60 feet (6 to 18 metres) deep. It grows to a length of almost three feet (one metre), has silvery-bronze flanks sprinkled with white spots, and gorgeous emerald eyes that reflect a diver's torchlight like cats' eyes, bringing a special magic to what might otherwise be a rather dull dive.