The anaspidacean head does not bear a carapace. Eyes may be on stalks, sessile on the head, or absent altogether. The first thoracic somite is fused to the head while the remaining seven thoracic somites are free. The first thoracic appendage is modified as a maxilliped, that is, it has a different morphology from the remaining seven pairs of thoracic limbs, and is modified as a feeding structure. Thoracic limbs two through eight have the endopod developed into full walking legs. On these appendages, the epipods, which emanate from the outside margin of the coxa, function as flattened gills, and the exopods, which come from the basis, function for water movement. Sometimes the exopods are not present. The pleopods may be strongly developed, reduced, or absent. In the Anaspididae, the telson and uropods form a tail fan, but in other families, the uropods are elongate and the telson short. Anaspidaceans can be up to 1.9 in (5 cm) in length, but some species are less than 0.39 in (1 cm). Color is usually a dull brown.
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