ARTICULATA. FF? 
In the Brachyura (pl. 78, figs. 1-9), the carapace is generally transverse, 
and square, oval, or circular, the abdomen is small, without a caudal fin, it 
is bent beneath and received into a depression of the thorax, and is not usec 
in locomotion. The eye peduncles are generally longer than in the Macrura ; 
there are two pairs of antenn, one pair of mandibles, two of jaws or 
maxille, three of foot-jaws, succeeded by ten feet, the first pair having a 
pinching claw, the rest simple, and adapted in most cases for walking, but 
sometimes for swimming. The abdomen is wider in the female than in the 
male, and is composed of seven segments ; but some of these are sometimes 
united together in the female, so as to present from four to six. Linneus 
included the various genera of Brachyura in his genus Cancer, which 
corresponds very nearly to the English name crab. They are divisible into 
four families. 
Fam. 1. Leucosiade. This family, called Oxystomes by Milne Edwards, 
includes the four sub-families, Calappine, Leucosiine, Corystiine, and 
Dorippiine, in which the shell is more or less orbicular, the eyes generally 
small, and the external foot-jaws triangular. 
The Calappine form part of Latreille’s Cryptopodes, named from the 
feet being partly hidden by the projecting margin of the carapace. The 
Leucosiine are much like the Cancridze or ordinary crabs. Philyra (pl. 
78, jig. 7) is a genus of small Crustacea, with the carapace circular and 
depressed. In the Corystiine, the external antennz are robust and rather 
long, and the sternal plate narrow. In Corystes, the anterior feet are much 
larger in the male than in the female, and the abdomen has five articulations 
in the former and seven in the latter. The Dorippiine (Dorippe, pl. 78, 
jig. 8), which form part of Latreille’s Wotopodes, have the sternal plate 
circular and bent upwards posteriorly, the cheliform feet short, the two next 
pairs long, and the one or two last pairs, which are generally much reduced 
in size, are placed higher than the others, as if upon the posterior part of 
the back. 
Fam. 2. Ocypodide. This family of Leach corresponds to the Catameé- 
topes of Milne Edwards, in which the carapace is depressed, rhomboidal or 
ovoid, and the eye peduncles long and slender. The following are the sub- 
families: Thelphusine, Gecarcinine, Pinnotherine, Ocypodine, Gonopla- 
cine, and Grapsime. 
Thelphusa is a genus of crabs which lives along the banks of freshwater 
streams. The Gecarcinine (Gecarcinus, pl. 78, fig. 4) are remarkable for 
having branchiz adapted to aerial respiration. They live among damp forests 
in holes which they make, and where they moult. Their food is vegetable, and 
they generally move about at night, or in wet weather. They visit the sea at 
certain periods, for the supposed purpose of depositing their eggs. They run 
with great agility, and like the crabs in general, in either direction. Pinnotheres 
ostreum is commonly found within the shell of Ostrea virginiana of the 
United States coast. In this genus the males are much smaller and more 
rare than the females. They are found within the shell of various bivalve 
Mollusca, as Pinna and Mytilus, where they are compensated for the 
weakness of their shell. The Ocypodine (Ocypoda, pl. 78, fig. 6; Gela- 
ICONOGRAPHIC ENCYCLOPZDIA.—VOL. IL. 21 3821 
