DECAPOD CRUSTACEANS OF THE BEAUFORT, N. C, REGION. 373 



The general aspect of the decapod fauna of the Beaufort region is subtropical. Un- 

 questionably the great influx of species have been from the south, and the comparatively 

 few northern ones that occur are evidently at a disadvantage. The Gulf Stream sweeping 

 up along the coast at no great distance from the shore has doubtless been the route by 

 which numerous crustaceans, often in the larval stages, have come northward. Some 

 of these have been able to establish themselves while others are more or less regularly 

 replaced by new individuals as the old ones are killed during the colder months of the 

 year. The offshore fishing banks " offer peculiarly favorable conditions for the life of 

 these tropical species of crustaceans, and of fishes, echinoderms, coelenterates, and 

 sponges as well, and have 5delded some 30 species of decapods which have rarely, if 

 ever, been taken closer to the shore. 



The Gulf Stream and the prevaihng south and southeast winds bring to the region, 

 and often into the harbor, great quantities of drifting Sargassum among which large num- 

 bers of the smaller pelagic crabs and shrimps have taken shelter. In nearly all cases, the 

 females of these species are laden with eggs, but it is probable that few if any of these 

 survive the journey into the shallower and quieter waters along the coast. Some of 

 the pelagic species, however, are so constant in their occurrence and their larval forms 

 are so frequently met with that it is evident that they breed at no great distance from, 

 if not within, the region. 



For the truly local fauna, comprising the species that are firmly established and which 

 can readily be obtained by ordinary methods of collecting, the shallow waters of the 

 sounds and Beaufort Harbor, with their broad expanses of sand and mud flats, and the 

 salt marshes which extend for miles along their margins offer an ideal home. The 

 shrimps and swimming crabs are found in abundance in the deeper waters or among the 

 eel grass near the marshes. Mud crabs and various burrowing species occur on the muddy 

 bottoms, and myriads of fiddler crabs are to be seen on the mud flats along the margin 

 of the marshes at low tide. In certain parts of the harbor there are areas of shelly bottom 

 of considerable extent, and it is in such places that shrimps of the genus Sicyonia and 

 crabs of the genera Lithadia, Spelceophorus and Heterocrypia occur. On the sandy bottoms 

 the purse crabs {Persephona) and the box crabs (Hepatus) are occasionally found along 

 with numbers of lady crabs (Ovalipes) and blue crabs, both Callinecies sapidus and 

 C. ornatus. The sand flats, especially if there is an admixture of mud, are good collecting 

 grounds for the burrowing and commensal species such as Upogebia affinis, Polyonyx 

 macrocheles , and the various species of Pinnixa. Among the beds of oyster shells Upo- 

 gebia and the species of Crangon are to be found. The sandy shores support such species 

 as Emerita talpoida, Albunea gibbesii, and ArewBus cribrarius. These same shores, but 

 in their higher levels, are inhabited by great numbers of the sand crabs (Ocypode albicans) 

 whose curious appearance is certain to command the attention of even the most unob- 

 servant visitor and whose fleetness of foot will astonish him. About the rock jetties and 

 the wharves the agile wharf crabs {Sesarma cinerea) are always in evidence. The fresh 

 waters of the region have been very inadequately explored but it may safely be said that 

 not more than the three species of crawfishes and one species of shrimp described in this 

 paper will be found there. 



a The location and character of these banks have been described by RadcUffe, Bureau of Fisheries, Economic Circular No. 8. 



