412 REPORT OF NEW JERSEY STATE MUSEUM. 



Lower surface of carapace laterally, above articulations of 

 chelipeds and first pair of ambulatory legs, hairy. Outer max- 

 illipeds with long ischium, merus a little longer than broad, and 

 other three terminal joints subequally small. Inner and outer 

 edges of outer maxillipeds densely hairy. Chelipeds subequally 

 enlarged, though left a little larger, and both more or less 

 smooth. Dactyl and pollex robust, approximated distally, with 

 molar-like tubercles as teeth, these rather obsolete, though large. 

 Propodus rounded convexly below, though with ridge on upper 

 inner edge well developed, also another broader but less defined 

 one parallel and external. Carpus with large inner triangular 

 tubercle above. Merus unarmed. First and second pairs of 

 ambulatory legs longest, and fourth shortest, though with 

 dactylus, propodus and carpus more compressed than others. 

 First and last pair of legs with ridges of close-set brush-like 

 setae on both edges of dactyls and lower edges of propodus. 

 Fourth pair of legs also with similar ridges of setae on upper 

 and lower edges of carpus, besides upper anterior edge of merus. 

 Dactyls of second and third feet with setae similar to others, only 

 little developed. Post-abdomen forms bell-shaped triangle in 

 contour in male, and in female much broader or ovate. 



Color greenish above, marked with yellowish spots, paler be- 

 low. Length of carapace 53 mm., width 68 mm. 



Remarks. — ^A northern species ranging from Virginia to New 

 England and northward, and also in Europe. It lives usually 

 near low-water mark. When disturbed it is a good runner. It 

 also lives about our larger tidal pools. In New Jersey I have 

 found it at Ocean City and Stone Harbor. My specimens at 

 present from Atlantic City Inlet, Townsend's Inlet and Turtle 

 Gut Inlet. Mr. Witmer Stone met with it at Point Pleasant. 

 Mr. W. T. Davis says it is not uncommon along the shores of 

 Staten Island. N. Y., particularly where rocks abound. 



Genus AREN/GUS Dana. 



Arcncrus Dana, Amer. Jnurn. Sci. Art.. (2) XII, 1851, p. 130. Type Portunus 

 cribrariiis Lamarck, monotypic. 



