Definition of purse crab in US English:

purse crab

noun

  • Any crab of the family Leucosiidae, in which the females have a rounded chamber on the abdomen in which the egg mass is enclosed; especially a crab of the genus Persephona, of the West Atlantic.

Origin

Early 18th century; earliest use found in James Petiver (c1665–1718), botanist and entomologist.