DECAPOD CRUSTACEANS OF THE BEAUFORT, N. C, REGION. 45I 



Genus UCA Leach. The fiddler crabs. 



Vca Leach, 1814, p. 430; Rathbun, 1897b, p. 154. 

 Gelasimus Latreille, 1817, p. 517. 



KEY TO THE SPECIES OP THE BEAUFORT REGION. 



o. Carapace fully one and one-half times as wide as long; color dark, often vrith blue on the front; size 



small; large chelipedof male with an oblique tuberculate ridge on the inner surface pugnax. 



aa. Carapace less than one and one-half times as wide as long. 



b. Thickness of body less than two-thirds the width of the carapace; color dark, usually with more 

 or less grayish toward the front margin; size large; large cheliped of male with an oblique tuber- 

 culate ridge on the inner surface minax. 



bb. Thickness of body two-thirds the width of the carapace; color light purplish gray mixed with 

 brown; size small; large cheliped of male without a tuberctilate ridge on the inner siu-- 

 face pugilator. 



Dca minax (Le Conte). Large fiddler crab. PI. xxxvn, fig. 3. 



Gelasimus minax Le Conte, 1855, p. 403: Coues, 1871. p. 121; Kinglsey, 1880, p. 148; Paulmier, 1905, p. 147. 



Gelasimus vocatoT Kingsley, i88oa, p. 399. 



Uca minax Rathbun, 1900, p. 585; Su mn er, 1911, p. 67s; Fowler, 1912, p. 450, pi. 144, 145. 



Carapace quadrilateral , about one and one-third times as wide as long, convex and nearly smooth 

 above; front deflexed; lateral regions nearly vertical; anterolateral angle slightly produced, continued 

 backward and inward as a low, but well-defined ridge and, above the orbits, entirely across to the oppo- 

 site side as a low revolute ridge ; a semicircular groove on each side inside the anterolateral angle. Orbits 

 large and open, their lower margin dentate. Front rather narrow. 



Eyestalks long, slender. Antennules and anteimae small, the flagellum of the former being hardly 

 visible. Chelipeds in the male very unequal, in the female equal and of small size. Large hand of 

 male tuberculate above and in front, ridged above, inner surface with a central, oblique tuberculated 

 ridge; fingers strong, meeting only at their tips, their cutting edges tuberculate and with a few larger 

 teeth at irregular intervals, immovable finger truncate at tip. Walking legs strong and sparsely hairy. 



Measurements of a male: Length of carapace, 20 mm.; width, 30 mm.; length of large hand, 56 mm. 



Color, chestnut brown becoming gray in front, chelipeds with red spots at the articulations, chelse 

 ivory white, legs olive or grayish brown. 



This is the largest of the three fiddler crabs foimd in the region and is to be looked for in the marshes 

 some distance back from the salt water. In such situations they dig holes, often considerably above 

 high tide level, which penetrate to a depth of i or 2 feet. In the moat at Fort Macon and along the 

 banks of the canal leading to the Neuse River U. minax may be found living where the water about them 

 is almost perfectly fresh. In some cases they build at the mouth of their burrow a low chimney or roof 

 over a short tunnel along the surface of the ground with the mud pellets which they bring up, but usually 

 the excavated material is scattered at some distance from the burrow. Females with eggs have been 

 found as late as August. 



Dca pugnax (Smith). Mud fiddler. PI. xxxvii, fig. 4. 



Gelasimus vocans Gould, 1841, p. 325; De Kay, 1844, p. 14 (pt). 



Gelasimus palustris Stimpson, 1859, p. 62 Cpt.). 



Gelasimus pugnax Smith, 1869, p. 131; Coues, 1871. p. 121; Kingsley, 1878-79, p. 322: Paulmier, 1905. p. 147. 



Gelasimus vocaior Kingsley, 18S0, p. 147. 



Uca puffnax Rathbun, 1900, p. 585; Sumner, 1911, p. 675; Fowler, 1912, p. 454, pi. 146, 147. 



Carapace one and one-half to one and three-fifths times as wide as long. Large hand of male slender, 

 its inner surface with a tuberculate ridge like that of U. minax; fingers long and slender, widely gaping 

 at base and meeting only at their tips; movable finger strongly curved, evenly denticulate; immovable 

 finger with one larger tooth near the middle, its inferior border nearly straight, its tip sometimes 

 depressed. 



Measiu-ementsof amale: Length of carapace, 10.5mm.; width, 17 mm.; length of large hand, 30 mm. 



Color of carapace, dark olive, almost black, becoming bluish on the front ; chelipeds brownish yellow ; 

 legs brown. 



