Figure 180. — Panopeus herbstli H. Milne Edwards. A, 

 animal in dorsal view, walking legs not shown ; B, right 

 chela in frontal view ; 5 mm. indicated. 



penultimate segment nearly parallel; terminal 

 segment broader than long, rounded at tip. 



Chelipeds heavy, finely granulate ; carpus with- 

 out groove on superior surface and with a blunt 

 internal spine; hands unequal and dissimilar, 

 large one with dactyl curved and strongly toothed 

 at base, dactyl of smaller more nearly straight ; 

 fingers dark, with color extending somewhat on 

 palm. 



Measurements. — Carapace: male, length, 26 

 mm.; width, 38 mm. 



Variations. — Rathbun (1930a) separated this 

 species into a number of forms on the basis of 

 structural characteristics but considered these the 

 result of response to environment rather than 

 genetic differences. Intermediates may occur in 

 any locality; thus, the forms are not always 

 easily separated. 



Ryan (1956) described a persistent, central, 

 oval, red spot or structure on the inner surface of 

 the ischium of the third maxillipeds of both sexes. 

 Mrs. Peggy Keney of the U. S. Fish and Wildlife 

 Service Bureau of Commercial Fisheries, Bio- 

 logical Laboratory, Beaufort, N.C., found this 



spot to occur on 100 percent of males and 55 

 percent of females in the Beaufort area. A sam- 

 ple of 596 specimens was examined. 



Habitat. — Depth distribution for the species 

 ranges from the intertidal zone to 12 fathoms. 

 Ryan (1956) found the species to be rare in 

 Chesapeake Bay in a salinity range of 13.95 to 

 19.04 °/ 00 . Tlie depth distribution there was 2 to 

 6 fathoms and at each collection spot the bottom 

 was composed of soft mud with few oyster shells. 

 McDermott and Flower (1953) found the species 

 common on oyster beds in Delaware Bay, where it 

 commonly cracks and eats small oysters and the 

 barnacle Balanus eburneus. The toadfish was con- 

 sidered a common predator. 



In North Carolina and South Carolina, this is 

 one of the most common crabs of estuarine re- 

 gions, found wherever the bottom is muddy or 

 covered with shells or stones. In some localities 

 along edges of the higher marshes, it is found in 

 burrows and is frequently associated with Sesarma 

 reticulata and Uca minwx. 



In the West Indies, collections have been made 

 from mangrove roots, sponges, and coral reefs. 



Type locality. — North America. 



Known range. — Boston, Mass., to State of 

 Santa Catarina, Brazil; Bermuda. 



Remarks. — This common xanthid crab has a 

 fossil record dating from the Miocene in North 

 America, and the genus Panopeus has a record 

 extending from the Eocene to the present (Rath- 

 bun, 1935). 



Ovigerous females are known virtually the year 

 around in Florida. They are known through late 

 spring and summer in the Carolinas, in July in 

 Maryland, February to September in various 

 parts of the West Indies, and August to October 

 in southern Brazil. 



Ryan (1956) gave carapace widths of mature 

 males as 8.3 to 37.3 mm., and of mature females 

 as 21.6 to 27.8 mm. A specimen 45 mm. wide was 

 found at Beaufort, N.C., in 1960 (Mrs. Keney, 

 personal communication), and Wass (1955) re- 

 ported a male 55 mm. wide. 



Costlow and Bookhout (1961a) reviewed early 

 descriptions of larvae and described and illus- 

 trated four zoeal and one megalops stage reared 

 in the laboratory. 



Costlow, Bookhout, and Monroe (1962) reared 

 the larval stages under 12 different conditions of 



MARINE DECAPOD CRUSTACEANS OF THE CAROLINAS 

 763-049 0—65 14 



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