3IO REPORT OF NEW JERSEY STATE MUSEUM. 



last case mostly soft and asymmetrical ; sixth abdominal somite sel- 

 dom without appendages homologous with caudal swimmerets ; front 

 not united with epistome across ophthalmic somite; last thoracic seg- 

 ment independent, when not atrophied movable ; genital ducts never 

 open on sternum ; antennal peduncle carries an exopodite, this never 

 foliaceous. anomura 



aa. Abdomen shorter than cephalothorax, beneath which it folds permanently ; 

 front joined with epistome aci'oss hidden ophthalmic somite to form an 

 interantennular septum; eyes enclosed in orbits or tubular cavities of 

 carapace ; antennules and antennae small ; bases of antennules sunk in pits 

 of carapace; antennee without exopodite; third maxillipeds flattened, 

 valve-like ; thoracic sternum usually, not always, broad, last segment 

 fused with others ; sixth somite mostly without appendages, when rarely 

 present {Dromiidce) appearing as pair of small lateral plates intercalated 

 between sixth and seventh somites ; genital ducts of female usually, not 

 always, open on sternum, and those of males sometimes also. 



BRACHYURA 



Sub-Order MACRURA. 



The Macrurans. 



Body elongate, cephalothorax less than half its total length. 

 Front not fused with epistome. Carapace generally produced 

 anteriorly into a rostrum and generally covers ophthalmic somite. 

 Abdomen large and symmetrical, more or less completely ex- 

 tended behind cephalothorax, but never folded beneath it, ends 

 in symmetrical tail-fan with foliaceous lateral lobes (caudal 

 swimmerets). Thoracic sternum generally narrow. Abdominal 

 pleura behind first generally well developed, and terga commonly 

 overlap one another. Eyes seldom lodged in orbits. Antennular 

 peduncle generally rigid or its joints not folded, usually shorter 

 than flagella. Antennal peduncle commonly with all five joints 

 distinct and movable. Its second joint often carries an exopodite, 

 which usually large and foliaceous (antennal scale), sometimes 

 spiniform. Antennal fiagellum almost always very long. Ex- 

 ternal maxillipeds mostly elongate and pediform. Epipodites 

 often present on first four pairs of thoracic legs as well as on 

 maxillipeds. First pair of thoracic legs usually enlarged and 

 chelate, second pair also commonly chelate, and very often third 

 pair. Usually all abdominal somites, except telson, carry pair of 

 well-developed appendages. Commonly styliform appendix in- 



