KEY TO SUBORDERS, SECTIONS, SUPERFAMILIES, AND FAMILIES OP DECAPOD CRUSTACEANS POUND 



IN THE CAROLINAS— Continued 



aa. General form lobsterlike or crablike — Continued 



bb. Abdomen bent upon itself or flexed beneath thorax — Continued 



cc. Uropods rarely present, never biramous; abdomen small, permanently flexed beneath thorax; carapace fused 



with epistome; (first pair of legs always chelate or subchelate) Section Brachyura (p. 142). 



d. Anterior thoracic sterna very broad, posterior thoracic sterna narrow and keellike; posterior thoracic epimera 



largely exposed by reduction of branchiostegite Subsection Gymnopleura; Family Raninidae (p. 142). 



dd. Anterior thoracic sterna not usually broad, posterior thoracic sterna not keellike; posterior thoracic epimera 

 covered by branchiostegite. 

 e. Buccal frame triangular, prolonged forward to form a gutter; openings of oviducts generally sternal; first 



pleopods lacking in female Subsection Oxystomata (p. 146). 



f. Afferent branchial openings on either side of endostome Family Leucosiidae (p. 147). 



ff. Afferent branchial openings in front of bases of chelipeds Family Calappidae (p. 152). 



ee. Buccal frame roughly quadrate; not prolonged forward. 



f. Last pair of legs modified in form and dorsal in position; openings of oviducts coxal; first pleopods present 



in female Subsection Dromiacea (p. 143). 



g. Sternum of female with longitudinal grooves; eyes usually completely sheltered by orbits when retracted 



Family Dromiidae (p. 143). 

 gg. Sternum of female without longitudinal grooves; eyes incompletely or not at all sheltered by orbits 



when retracted Family Homolidae (p. 146). 



ff . Last pair of legs normal in position (rarely reduced or dorsal, Palicidae) ; openings of oviducts on 



sternum; first pleopods lacking in female Subsection Brachygnatha (p. 160). 



g. Body of medium width or broad in front; rostrum reduced or wanting. 



Superfamily Brachyrhyncha (p. 160). 

 h. Carpus of third maxillipeds articulating at or near anterointernal angle of merus; body usually round 

 or transversely oval; openings of vasa deferentia nearly always coxal. 



i. Distal articles of last pair of legs broad, thin and paddlelike... Family Portunidae (p. 160). 



ii. Distal articles of last pair of legs not paddlelike. 



j. Antennules folding longitudinally; outer maxillipeds long, overlapping epistome 



Family Cancridae (p. 174). 

 jj. Antennules folding transversely or obliquely; outer maxillipeds usually not overlapping epistome. 

 k. Body usually transversely oval; openings of vasa deferentia rarely sternal 



Family Xanthidae (p. 176). 

 kk. Body usually quadrate; openings of vasa deferentia sternal or, if coxal, passing along groove 



in sternum Family Goneplacidae (p. 201). 



hh. Carpus of third maxillipeds not articulating at or near inner angle of merus; body usually quadrate 

 (except Pinnotheridae) ; openings of vasa deferentia nearly always sternal; right chela not always 

 larger than left (except Palicidae). 

 i. Small, usually commensal crabs with small eyes and orbits; body usually somewhat rounded, adult 



females often with carapace somewhat membranous Family Pinnotheridae (p. 203). 



ii. Free living crabs with eyes not strikingly reduced; body usually quadrate, adult females with 

 carapace normal, 

 j. Last pair of legs dorsally placed and weaker than others; interantennular septum very thin 



Family Palicidae (p. 215). 

 jj. Last pair of legs not dorsally placed; not markedly weaker than others; interantennular septum 

 not very thin, 

 k. Front broad; eyestalks of moderate length or short; a gap of varying size between outer maxilli- 

 peds Family Grapsidae (p. 217). 



kk. Front with moderate width; eyestalks long; outer maxillipeds nearly, or quite, closing buccal 



area Family Ocypodidae (p. 225). 



gg. Body narrowed in front; rostrum usually distinct; orbits often incomplete 



Superfamily Oxyrhyncha (p. 235). 



h. Chelipeds not much larger than other legs Family Majidae (p. 236). 



hh. Chelipeds much larger than other legs Family Parthenopidae (p. 266). 



MARINE DECAPOD CRUSTACEANS OF THE CAROLINAS 13 



