• Carapace usually broad or net longer than broad or as long as broad with well marked side edge
• 4th and 5th legs small
• 4th and 5th subdorsal and usually prehensile

• Carapace short and squarish
• Addomen not fully hidden beneath carapace
• last two pairs of legs reduced and subdorsal
• antennule larger

• Carapace round,spherical or hemispherical
• antennae small
• lnhalent branchial openings at base of external maxillipeds

• Carapace round, spherical or hemispherical
• antennae small
• inhalent branchial openings in front of basal segment of cheliped

• Carapace usually pyriform (conical shaped)
• basal segment of antenna fused with epistome, also with front,orbits in complete
• chelipeds shorter than legs

• Carapace triangular or pentagonal
• basal segment of antenna small not fused with epistome or front
• chelipeds stouter than leg

• Carapace usually round or oval
• right chela larger than left
• last leg flattened, adopted for swimming
• usually a small lobe at inner angle of endopodite of first maxilliped

• Legs not adapted for swimming
• Branchial regions not swollen
• Carapace anteriorly broadened
• No inner lobe on endopodite of first maxilliped

• Legs not adopted for swimming
• Branchial region not swollen
• Carapace squarish

• Body squarish or rounded or fransversely elliptical
• Right chela not larger than left
• Carapus of third maxilliped not articulating with merus
• small,symbiotic or parasitic crab

• Boby squarish
• Carpus of third maxilliped not articulating with merus
• Last legs not dorsally placed
• Fornt very narrow, orbits very elongate and oblique covering almost anterior portion of carapce

• Last legs not dorsally placed
• A gap between third maxilliped
• sides of body strongly arched, front broad
• Rarely true land crabs

• Last pair of leg not dorsally
• A gap between third maxillipeds
• sides of body strongly arched
• Carapace transversely oval, front narrower
• Land crabs

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