390 BULLETIN 97, UNITED STATES NATIONAL MUSEUM. 



Dactylus much longer than the pollex and curving downward past 

 the tip of the latter, leaving a wide gape throughout the entire length. 



Ambulatory legs long-hairy, merus-joints wrinkled and in the first 

 three paire enlarged toward the middle. 



Female narrower than male. 



Color. — The three articulations of the large joints of the greater 

 claw have a red spot in life. 



Measurements. — Male (12781), length of carapace 25.2, width of 

 same 38 mm. 



Habits. — Lives in marshes of estuaries of rivers and brooks, in 

 brackish or even quite fresh water. Abundant in the mangroves 

 (Colombia, Pearse). According to Fowler^ — 



It is a vegetarian, feeding on the algae which grows In muddy salt-marshes. 

 This is often a minute-green algoid plant covering the surface of the muiL 

 The male uses its small claw exclusively in obtaining its food and conveying It 

 to the mouth. The female uses either of her small oues indifferently. In 

 enlarging its burrows the crabs were seen to scrape off the mud from the 

 Inside by means of the claws of the ambulatory legs, and having formed the 

 mud Into a pellet, pushed it up out of the hole by means of the elbow joint at 

 the base of the great claw, when this is folded down. The crab was also 

 found to construct a regular oven-like arch of mud over the mouth of its bur- 

 row. This archway Is horizontal and large enough to contain the crab, who 

 quietly sits in this curious doorway on the outlook for his enemies of all kinds. 



Range. — From "Wareham, Massachusetts, to Texas. Colombia 

 (Pearse). 



Material examined. — 



Wareham, Massachusetts; July 21, 1887; U. S. Fish Coram.; 3 

 males (12781). 



Seekonk River, Ehode Island; F. P. Drowne; low tide near brack- 

 ish water under stones; 2 males, 1 female (19569) ; burrows on shore 

 of river, burrows in groups and located near eel grass; 2 males, 1 

 female (19570). 



Newport, Rhode Island; 1880; U. S. Fish Comm.; 3 males (4909). 



Chesapeake Beach, Maryland; found in marsh grass; July 4, 1914; 

 C. R. Shoemaker; 2 females (1 ovig.) (4910G). 



Point Lookout, Maryland; J. E. Benedict; 3 males, 1 female 

 (1G159). 



St. Georges Island, Maryland; June 30-July 6, 1890; H. M. Smith; 

 1 male (22807). 



North Carolina; John W. Hays, jr.; 1 male (13890). 



Winyah Bay, South Carolina ; Jan., 1891 ; Fish IlawJc; 5 males, 1 

 female (17487). 



Bulls Island, South Carolina; fresh pools near beach; Mar. 21, 

 1891; 9 males (17183). 



^ Ann. Sept. New Jersey State Museum, 1911 (1012), p. 453. 



