160 



BULLETIN 97, UNITED STATES NATIONAL MUSEUM. 



the 



legs 

 tiio 



Description of male. — Carapace smooth, punctate, piinctae small 

 and scarce in middle third, large and more numerous elsev.'here. A 

 deep groove separates anterior cardiac region from gastric and bran- 

 chial regions; a sharp, granulate antero-lateral crest which does not 

 reach cervical suture; a transverse ridge crosses middle of cardiac 

 region between bases of feet of last pair; outer angles hairy; poste- 

 rior border short, a little concave. Front not prominent, truncate, 

 with a submarginal groove, produced backward at middle. 



Chelipeds smooth, punctate; chelae suboval; fingers horizontal, of 

 subequal length, tips strongly hooked and overlapping when closed, 

 leaving a gape; a sharp, finely milled crest runs from tip of poUex 

 backward and upward, about two-fifths length of palm ; a tooth on 



dactylus near mid- 

 dle of prehensile 

 edge, one on pol- 

 lex distal to 

 middle. 



Dactyli of 

 straight in 

 main, the fourth 

 one convex poste- 

 riorly and slightly 

 concave anteriorly. 

 First leg slender, 

 reaching to end 

 of propodus of 

 second; second 

 stouter, to middle 

 of dactylus of third; third very stout, merus If times as long as 

 wide, distally narrowed, upper and lower margins finely granulate; 

 fourth leg very short, reaching beyond merus of third by half length 

 of dactylus. 



Color. — Yellowish grey (Stimpson). 



Measurements. — Male (17952), length of carapace 5.8, width of 

 same 11.8 mm. Female (4912G), length of carapace 7.8, width of 

 same 15.3 mm. 



Habitat. — "Lives with the lobworm {Arenicola cristata) in its 

 hole in the sand, which is not lined by any tube. The young occur 

 in the early spring on slimy shores at low-water mark" (Stimpson). 

 Range. — North Falmouth, Massachusetts ; Chesapeake Bay to Sar- 

 asota Bay, Florida. 

 Material examined. — 



North Falmouth, Massachusetts; Aug. 5, 1914; F. M. Root; 1 

 female (4912G). 



Fig. 



a 



99. PiNNlXA CYLINDRICA, MALE (17952). O, GUTEa MAX- 



iLLirED, X 10 ; b, audome.v, X 73. 



