DECAPOD CRUSTACEANS OP THE BEAUPORT, N. C, REGION. 405 



Chelipeds subequal; carpus with four spines, graded in size, the proximal one being the largest; upper 

 surface with four prominent tuberculate ridges with deep channels between; the channels crossed by- 

 irregular septse forming a row of oblong pits between the ridges; the ridges and pitted channels continued 

 onto the hand but with less regularity in their arrangement; fingers tuberculate almost to their tips. 

 First three pairs of walking legs stout and with the three distal articles hairy. Fourth pair weak and 

 borne on the back. 



Length of a male, 7.5 mm.; width, 7 mm. 



Color, brownish red, the fingers vermilion. 



Two specimens of this crab were taken on the fishing banks in 14 fathoms and another off Cape 

 Lookout in 47 fathoms by the Fish Hawk in 1914. 



Genus POLYONYX Stimpson. 



Polyonyx Stimpson, 1858, p. 233. 



Polyonyx macrocheles (Gibbes). PI. xxix, fig. 8. 



Porcdlana macrocheles Gibbes, 1S50, p. 191. 



Polyonyx macrocheles Stimpson, 1857-1860, p. 239; Benedict, 1901, p. 138; Stunner, 1911, p! 669. 



Integument firm and smooth. Carapace transversely oval, about one-fourth wider than long; 

 front hardly produced, its margin slightly sinuous; infolded lateral portions separated from the rest of 

 the carapace by a deep fissure. Antenna slender, about one and one-half times as long as body; its 

 basal segment massive, completely filling the fossa in which it is lodged and bearing the flagellum at its 

 outer angle. Chelipeds xinequal, long and distorted; hand of the larger one nearly twice as long as 

 carapace; superior margin convex, inferior margin nearly straight and with a fringe of long hairs; fingers 

 short, hooked at tip and toothed on cutting edges, movable one falcate; carpus as long as hand minus 

 the fingers, thick, deeply excavated along front surface to receive the retracted hand ; carpus subcubical, 

 likewise excavated in front. Second, third, and foiuth legs normal but with short dactyli which bear 

 brushes of stiff hairs. Abdomen small, much flattened; ttropods small; telson divided into small plates. 



Meastu-ements of a male: Length of carapace, 7 mm.; width of carapace, 9.25 mm.; length of hand, 

 13 mm. 



Color, grayish white, sometimes stained with brown. 



This ctuious little crab is a common commensal of Chaitopterus pergamentaceus whose U-shaped 

 tubes may be fotmd imbedded in the shoals in various parts of the harbor. It is very rarely foimd 

 outside these tubes; in fact when grown, it is probably impossible for it to escape from the tube in which 

 it has taken up its abode .0 A male and a female are usually found together in the end of the tube 

 opposite the one occupied by the worm. The breeding season extends through the whole summer, 

 females carrying eggs having been collected from Jime 21 to October 25. 



Genus EUCERAMUS Stimpson. 



Euceramus Stimpson, i860, p. 445. I 



Euceramus prselongus Stimpson. PI. xxix, fig. 3. 



Euceramus praeUmgus Stimpson, i860, p. 445; Kingsley, 1878-79, p. 408; Benedict, 1901, p. 138. 



Carapace subcylindrical, elongate, the sides slightly arcuate, with minute irregular, transverse 

 rugae anteriorly; anterolateral margins with two spines on each side behind the antennte; front tridentate, 

 the median spine being abotit twice as long as the lateral ones. Eyes well developed but almost con- 

 cealed beneath the front. Antennules very short. Antennse about three-fourths as long as body, their 

 flagella sparsely covered with very fine hairs. Third maxillipeds large and forming a subquadrate shield 

 which extends laterally almost to the edge of the carapace. Chelipeds stout; hand slightly roughened 

 and hairy; fingers about as long as palm, not gaping. Second pair of legs shorter than the third and fotuth 

 pairs. Fifth pair reduced and turned dorsally. Abdomen small, its distal segments very narrow and 

 the tu-opods vestigial. 



Measurements: Length of carapace, 8 mm.; width of carapace, 3.75 mm. 



a Enders: Notes on the commensals fomid in llie tubes of Cliccloplerus pergamentaceus, American Naturalist, vol. xxxlx, 

 p. 37-40. 1905. 



