154 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



The single tentacle scale is very large, squamiform, slightly oval, 

 furnished on its distal border with a row of very fine denticulations 

 (fig. 6J). 



The color of the specimens in alcohol is yellowish gray. 



Affi/nities and distinctive features. Amphiura commutata is very 

 easily distinguished from the species of Amphiura indeed, very few 

 in number in which the ventral surface of the disk is naked and 

 which possess only a single tentacle scale. The forms which ap- 

 proach it most closely are A. concinna Koehler, found by the Siboga 

 in the Sunda Archipelago, and A. glabra Lyman, which the Chal- 

 lenger collected in 4 N. latitude and 127 E. longitude at a depth of 

 500 fathoms; both are deep-sea forms with which the Albatross 

 species can not be confused. 



AMPHIURA DEJECTA, new species. 



Plate 66, figs. 4, 5. 



Locality. Albatross station 5592; Sibuko Bay, Borneo, and vicin- 

 ity; Silungan Island (M.) bearing N. 1 Q W., 11.86 kilometers (6.4 

 miles) distant (lat. 4 12' 44" N., long. 118 27' 44" E.) ; 558 meters 

 (305 fathoms) ; September 29, 1909; gn. M. 



One specimen. 



Description. The diameter of the disk is 9 mm.; the arms are 

 broken off 20 mm. or 22 mm. from their base, but they can not be 

 very long, for the longest stump is already markedly narrowed at 

 the place where it is broken off; these arms are somewhat flattened, 

 and of medium size. 



The disk is rounded. The dorsal surface is covered with numerous 

 subequal imbricated plates, becoming smaller at the periphery of the 

 disk, and a little larger in the vicinity of the radial shields; each 

 interradial space includes from ten to twelve rows of plates. There 

 is not the least indication of primary plates. The radial shields are 

 rather small, two and a half times as long as broad, with the proximal 

 angle pointed and the external border very convex. The two shields 

 of each pair are close together but not in contact outwardly, and 

 slightly divergent inwardly. Their length is much less than half 

 the radius of the disk. 



The ventral surface is covered with extremely small, imbricated, 

 very closely crowded plates, but in the immediate vicinity of the 

 mouth shields these plates become rounded, and are simply in contact, 

 sometimes even showing small bare spaces between them. The geni- 

 tal slits are narrow. 



The mouth shields are longer than broad, lozenge-shaped, with the 

 proximal sides elongated and the distal sides shorter ; the four angles 

 are rounded. The triangular adoral plates are rather small, and are 



