168 CRUSTACEA—EUCARIDA—DECAPODA CHAP. 
It is not much reduced in size, and the pleopods of the sixth pair 
are fairly well developed, but it is usually carried flexed towards 
the thorax, and is never a powerful locomotory organ as in the 
Maerura. The antennal scale, if present at all, is a mere spine, 
not the large leaf-like structure of the Macrura; and there is never 
a partition between the two first antennae as in the Brachyura. 
The last or last two pairs of pereiopods are reduced, and are 
turned on to the dorsal surface or carried inside the branchial 
chamber ; but this curious character is met with again in certain 
Brachyura (Dromiacea and Oxystomata). 
Tribe 1. Galatheidea.. 
These are symmetrical crabs with a long carapace; the 
abdomen, which is as broad 
as the carapace, is always 
carried flexed under the 
thorax, and the sixth pair 
of pleopods are expanded to 
form with the telson a fan- 
like tail. The most anterior 
pereiopods are always much 
elongated and chelate ; while 
the last pair are much re- 
duced, and either turned up 
on to the dorsal surface, or 
else carried in the branchial 
chamber. The exact mean- 
ing of this last characteristic 
in these forms is doubtful ; 
some of the species are said 
to carry shells temporarily 
upon their backs, a proceed- 
ing probably assisted by the 
last pair of thoracic limbs, 
Fic. 114.—Dorsal view of Munidopsis hamata, while in others their limbs 
ee pee ae figure prepared may be used for cleaning 
out the branchial chamber. 
Most of the Galatheidea, for instance, the common Porcellana and 
1 Milne Edwards and Bouvier, Ann. Sci. Nat. (7), xvi., 1894, p. 91. 
