Figure 179. — Eurypannpeun depressus (Smith). A, ani- 

 mal in dorsal view, walking legs not shown ; B, large 

 chela in frontal view ; 5 mm. indicated. 



Habitat. — In Chesapeake Bay, Ryan (1956) 

 found this species in greater abundance on oyster 

 bars than any other species of mud crab, and 

 evidence was presented showing a positive rela- 

 tionship between presence of oyster shells and this 

 species. Others have noted a similar habitat pref- 

 erence (Lunz, 1937a). In the bay, the depth range 

 was 1 to 15 fathoms (Cowles, 1930, in part), and 

 the salinity range occupied was 4.5 to 20.1 °/ 00 . 

 Elsewhere the species occurs from shore to 26 

 fathoms. 



Type locality. — New Haven, Conn. 



Known range. — Massachusetts Bay through 

 Florida (east and west coasts) to Texas; Ber- 

 muda ; West Indies. 



Remarks. — Ryan (1956) gave much detail on 

 the life history of this species in Chesapeake Bay. 

 Ovigerous females were collected from June to 

 September. Elsewhere, Rathbun (1930a) and 

 Lunz (1937a) reported such females in April 

 from Virginia and South Carolina, September 



from Mississippi and the Leeward Islands, No- 

 vember and February from Florida. Zoeal stages 

 have been studied by Hyman (1925) from plank- 

 ton tows made in the Beaufort, N.C., area. Cost- 

 low and Bookhout (1961b) worked out the entire 

 larval and postlarval history in captivity and 

 illustrated four zoeal stages and a single megalops 

 stage. Immature males from Chesapeake Bay 

 ranged in width from 3.2 to 6 mm. and females 

 from 3.6 to 6.4 mm. 



Maturity was considered to be attained at 

 widths of 5.1 to 6 mm. in males, and 5.5 to 6.4 mm. 

 in females. The mature individuals range widely 

 in size, up to a width of 21 mm. for females, and 

 ovigerous females show a range of 6 to 17 mm. 

 Such a broad range of sizes among mature in- 

 dividuals suggested to Ryan that growth and 

 molting continue after maturity is reached. 

 Maturity may be reached in the first summer 

 after eggs have hatched. 



McDermott (1960) found that E. depressus is 

 a predator on oyster spat in southern New Jersey 

 but not so serious a pest as P. herbstii. 



Genus Panopeus H. Milne Edwards, 1834 



Rathbun, 1930a, p. 333. 



KEY TO SPECIES IN THE CAROLINAS 



a. Dark color of immovable finger continued more or less 

 on outer surface of palm, especially in males ; no distal 

 groove on carpus of chelipeds herbstii (p. 190). 



aa. Dark color of immovable finger not continued on outer 

 surface of palm ; carpus of chelipeds with shallow 

 groove parallel to distal margin occidentalis (p. 198). 



Panopeus herbstii H. Milne Edwards. Common mud crab 



Figures 180, 183M 



Panopeus herbstii H. Milne Edwards. 1834, p: 403.— Hay and 

 Shore, 191S, p. 437. pi. 34, fig. 9.— Rathbun, 1930a, p. 335. text- 

 figs. 52-53, pi. 156, figs. 1-3 ; pi. 157, figs. 1-3 (rev.). 



Recognition characters. — Carapace approxi- 

 mately two-thirds as long as wide, regions well 

 marked, surface sparingly granulate. Antero- 

 lateral margins w T ith five teeth; first two teeth 

 coalescent; third and fourth larger, prominent, 

 and with arcuate outer margins and acute tips; 

 fifth smaller, acute at tip and with outer margin 

 straight. A transverse ridge extending inward 

 from fifth tooth, and a shallow groove from 

 fourth tooth. Front wide, not produced, with 

 narrow median fissure; anterior margin of each 

 half sinuous. Male abdomen witli sides of 



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