446 BULLETIN OF THE BUREAU OF FISHERIES. 



smooth on both edges and meeting its fellow only at the tip; hand of female smaller, its palmar edge 

 oblique and the immovable finger considerably longer than in the male. Second and third pairs of legs 

 slender; fourth pair longer and much stouter, conspicuously pubescent and with the inferoposterior 

 margins of the third, fourth, and sixth segments dentate; fifth pair like the fourth, but smaller. 



Measurements of a male : Length of carapace , 5.25 mm.; width, 12 mm.; length of hand , 5 mm. 



Color, nearly white, but usually much obscured by the brown or blackish hairs and the dirt collected 

 in them. 



This crab lives commensally with the worms Chreiopterus pergamentaceus and Amphitrite ornaia and 

 is seldom found outside their tubes." 



Pinniza sayana Stimpson. PI. xxxvi, fig. 3. 



Pinnixa sayana Stunpson, 1S59, p. 236: Kingsley, 1878-79, p. 323; Sumner, 1911. p. 674. 

 Pmnixa cyliiidrica Smith, 1873, p. 546. 



Carapace smooth and polished, lightly pubescent on the sides, depressed at the middle, and with 

 a low, ill defined, transverse ridge parallel with and close to the posterior margin extending about one- 

 third tlie width of the carapace; two similar ridges on the anterolateral slope, distant from but nearly 

 parallel with each other, the superior one curving inward and defining the branchial region; front 

 deeply grooved above. 



Hands stout, compressed, hardly twice as long as broad; immovable finger very short; movable 

 finger strongly curved; both fingers toothless. Walking legs smooth, penultimate pair larger than the 

 others, but not so much so as in P. chcctopterana. 



Measurements of a male: Length of carapace, 3 mm.; width, 6 mm. 



Color, almost white, but more or less stained with brown. 



This crab, tlie carapace which resembles that of P. cyliiidrica, while its hands are more like those 

 of P. chceiopterana, is said to be occasionally found in the sand-walled tubes of Arenicola cristata. The 

 specimens from which the species was originally described by Stimpson were dredged in 6 fathoms, 

 sandy mud, off the mouth of Beaufort Harbor. 



Pinnixa cristata Rathbun. PI. xxxvi, fig. 5. 



Pinniza cristata Rathbun, 1900, p. 589. 



Carapace smooth, polished, and very slightly pubescent at the extreme outer corners, not depressed 

 in the middle and with a conspicuous sharp, almost straight ridge which extends without a break 

 entirely across the shell a little in front of the posterior border; anterolateral ridge less conspicuous. 



Chelipeds stout and constructed like those of C. chmtopterana, but perfectly smooth except for a 

 band of fine hair along the lower margin on the inner siu^ace. Walking legs somewhat longer than 

 those of related species and sparsely hairy along the margins only. 



Measurements of a female: Length of carapace, 4.3 mm.; width, 10 mm. 



The only known specimen of this species was collected at Beaufort many years ago by Prof. H. E. 

 Webster, of Union College, N. Y., and is now in the United States National Museum. No data accom- 

 panied it, so we are iminformed as to its mode of life. It doubtless lives as a commensal in the tube of 

 one of the many species of worms and should be looked for with care . In general appearance it resembles 

 P. cyliiidrica, but has a hand like P. sayana. The shell is broader in proportion to the length than in P. 

 cylindrica, however, and the legs are markedly more slender. The long, unbroken ridge across the back 

 is a mark that can hardly be overlooked. 



Pinnixa cylindrica (Say). PI. xxxvi, fig. 2. 



Pinnotheres cylindricum Say, 181S, p. 452; De Kay, 1844. p. 13. 



Pinnixa cylindrica White, 1846, p. 177: Stimpson. i860, p. 235; Kingsley, 1878-79, p. 324. 



Pinnixa Iceviffaia Stimpson, 1859. p. 68. 



Carapace smooth, polished, punctate, pubescent at the extreme outer comers, depressed in the 

 middle, a very inconspicuous transverse ridge parallel with and close to the posterior margin, and a 

 more conspicuous anterolateral ridge; front bilobed, but not as deeply grooved as in P. chcEtopterana or 

 P. sayana. 



a Enders, H. F.: "Notes on the commensals found in the tubes of Chcetcpterus pergamentaceus," Amer. Nat., vol. xxxix, 

 190S. p. 37. 



