436 BULLETIN OP THE BUREAU OP PISHERIES. 



c. Antennje not excluded from orbits. 



d. Teeth of anterolateral margins sharp-pointed. 

 e. Dactyl of large hand with a large basal tooth. 



/. Outer surface of carpus smooth or nearly so Panopeus. 



ff. Outersiu^aceof carpus with agroove parallel with the distal margin Hexapanopeus. 



ee. Dactyl of large hand without a large basal tooth. 



/. Fingers of small hand spoon-shaped at their tips Eurypanopeus. 



ff. Fingers of small hand not spoon-shaped at tlieir tips Neopanope. 



dd. Teeth of anterolateral margins blunt-pointed or rounded. 



e. Front with two rotinded lobes Eurytium. 



ee. Front with two lobulate lobes Menippe. 



cc. Antennje excluded from the orbits Eriphia. 



bb. Carapace hairy or with extensive pubescent areas, front and anterolateral border with spines or 

 spiniform teeth. 



c. Carapace spiny or granulate and with plumose hairs Pilumnus. 



cc. Carapace nodose anteriorly, pubescent posteriorly Lobo pilumnus. 



aa. Frontal margin transversely grooved so as to appear double. 



6. Carapace more or less nodose in front, fingers black Leptodius. 



bb. Carapace with conspicuous transverse ridges, fingers white or brown Rhithropanopeus. 



Genus HEXAPANOPEUS Rathbun. 



Hexapanopeus Rathbun, 1898. p. 273. 



Hexapanopeus angustifrons (Benedict and Rathbun). Narrow mud crab. PI. xxxiv, fig. 7. 



Panopeus angustifrons Benedict and Rathbun, 1891, p. 373. 

 Hexapanopeus angustifrons Rathbun, 1898, p. 273; Sumner, 1911, p. 673. 



Carapace about two-thirds as long as wide, convex from front to back, regions fairly well marked, 

 surface finely granulate; anterolateral edge thin and upturned and divided into five teeth, of which the 

 first two are separated by a well-defined sinus, the third and fourth are successively broader and the 

 fifth is shorter, narrower, and more distinctly directed outward ; from the foiuth and fifth teeth well- 

 defined ridges extend obliquely inward and backward for a distance of about twice the length of the 

 teeth; front narrow and produced, divided by a prominent V-shaped notch into halves, each of which 

 is bilobate, the markedly sinuate anterior border forming a broad inner and a small and inconspicuous 

 outer lobe. 



Chelipeds strong, granulate, and finely rugose; meros with a well-developed tooth on the upper 

 margin; carpus with a deep groove parallel to the distal margin, an obtuse tooth at the inner angle, and 

 the superior surface rough and more or less tuberculate; hands unequal and dissimilar; propodus 

 usually with a fairly strong costa above and indications of one on the outer surface; both these costae 

 are continued onto the fingers, which are strong and inclined to be hooked at their tips; the movable 

 finger of the larger hand has a strong tooth at the base. 



Length, 19.5 mm.; width, 28mm. 



Color, variable, sometimes a uniform brownish yellow or even light buff, but usually a dark red- 

 dish brown or dark gray, the females usually darker than the males and often more or less spotted. In 

 both sexes the fingers are black or dark brown at the base, lighter at the tips; the dark coloration is not 

 extended onto the hand, but stops abruptly well within the base of the fingers. 



This little crab occiu-s in various parts of the harbor, especially where the bottom is covered with 

 old shells. It is frequently brought up in the dredge in the channel off Morehead City and may be col- 

 lected in the shallow water about Bird Shoal. It appears to like to hide among the masses of ascidian- 

 covered shells that are so abundant in these localities. In size it ranks far below the common Panopeus 

 herbstii, but is rather larger than the other mud crabs of the region. It comes to sexual mattirity at a 

 very early age, specimens less than 12 mm. across having been found with eggs. 



