A complex fluid filled invagination contained within the swollen base of the antennule and responsible for the sense of balance [Ingle, 1983].
Diminutive organ providing sense of balance, present in most crustaceans [Moore and McCormick, 1969].
(Order Isopoda):
Small saclike sensory organ, usually containing a granule(s), used to indicate to the animal its orientation; present singly or paired on the pleotelson of some anthurideans [Wetzer et al. 1997].
Crustacea glossary. Natural History Museum of Los Angeles County. 2011.