THE CRUSTACEA OF NEW JERSEY. 399 



a longitudinal groove on outer and inner edges. Upper edge of 

 dactylus punctate. Outer surface of pollex with two longitudinal 

 ridges, converge toward apex, distinct on outer surface and 

 obsolete on inner surface. Inner palm smoothly convex, outer 

 surface with two longitudinal median ridges. Both edges of 

 carpus and hand with series of minute granules, and several 

 patches on upper surface of former. No large tooth at base of 

 dactyl or on hand. Merus and carpus subequal. Ambulatory 

 feet more or less similar, hairy on outer portions, and posterior 

 pair a little shorter, its dactyls also shorter. 



Color more or less dull brownish, paler below. Chelipeds 

 brownish above, paler below, and fingers pale brownish, not con- 

 trasted with rest of propodus. Ambulatory legs all brownish, 

 paler below. Length of carapace 8.5 mm., width 10.3 mm. 



Remarks. — ^Found along the Atlantic Coast from Massa- 

 chusetts to Florida, though, unlike our other related species, it 

 ascends to fresh water in the tidal regions of the Coastal Plain. 

 It lives in muddy waters, often among submerged vegetation or 

 under stones, roots, etc. It ranges also into the salt marshes of 

 our bays and sounds, and along the coast. My specimens, from 

 Cedar Svv^amp Creek in fresh water above Petersburg Bridge, 

 where I found it in cold weather, though not abundant. Though 

 my largest example measures as stated above, the species attains 

 a length of 11 mm. and a width of 14.5 mm. for the dimensions 

 of its carapace. Characteristic of this species are the ridged or 

 keeled chelipeds and the pale fingers. 



It occurs in Dennis Creek, as I have seen examples obtained 

 from there many years ag^o, though have not met with it myself 

 while collecting in that locality. 



I found a number in the purely fresh water of the Elk River 

 at Elk Neck, in Cecil County, Maryland, on June 3d, 191 1. 

 Numerous fishes, as young Alosa sapidissima, Anguilla chrisypa, 

 Abramis crysolcucas, Fmididus heteroclitis macrolepidofits, F. 

 diaphanus, Tylosurus marinus, Menidia heryllina, Morone 

 americanaj, Pomolobus pseudoharengus and Brevoortia tyrannus 

 were found associated. I also have an example from the Sassa- 

 fras River, in the same State, taken at Betterton. 



