OPHIUBANS OF UNITED STATES NATIONAL MUSEUM. 65 



two tentacular scales only on a few of its first brachial articles, but the scales dis- 

 played on the under face of the disk of A. fibulata are ill-shaped and different 

 from those of the upper face, its spines are plainly bihamuled and the mouth shields 

 are elongated ; there is not the slightest connection between the two species. 



A. stimpsoni has been reported by Liitken and by Ljungman at various littoral 

 stations of the West Indies. H. L. Clark has noted it at Porto Rico, and, according 

 to Lyman, the Blake collected it at Barbados at a depth of 69 fathoms. 



AMPHItTRA MAGELLANICA Lyman. 



See for bibliography: 

 Koehler (08), p. 79. 



Albatross station 2770. Jan. 16, 1888. Lat. 48 37' S.; long. 65 46' W.; 58 

 fathoms; gy. s. bk. sp. 



Four specimens with fragments of the arms. All of them are of rather small 

 size, and, in the largest of them, the diameter of the disk is 5 mm. 



AMPHIURA DIDUCTA, new species. 



Plate 7, figs. 6-7. 



Albatross 1885, off Havana. No depth mentioned. One specimen. 



Type Cat. No. 32294, U.S.N.M. 



The disk is a little over 5 mm. in diameter; the arms are all incomplete; the 

 largest is preserved up to a length of 17 mm. 



The disk is pentagonal and pretty deeply excavated in the interradial spaces. 

 The upper face is depressed centrally as well as in the middle of the interradial 

 spaces. It is covered with small imbricated plates, subequal, and growing a little 

 larger only in the vicinity of the radial shields ; there is not the slightest indication of 

 primary plates. The radial shields are well developed and elongated, three and a 

 half times longer than wide, with an almost straight internal side and a convex 

 external side; they are in contact distally at their distal angles and a little divergent 

 proximally. The two shields of each pan- are separated by a chief range of elongated 

 plates which are succeeded by two other ranges of narrower plates. Their length is 

 equal to about half the radius of the disk. 



The under face is completely bare. The genital slits are fairly wide. 



The mouth shields, of middle size, are lozenge-shaped, as long as wide or a little 

 longer than wide, with a fairly opened proximal angle limited by two straight sides, 

 two lateral sides and a distal margin which is rounded or a little truncated. The 

 adoral plates are triangular, broadly widened without, narrowed, and in contact 

 within. The oral plates are small and short. The two oral papillae on each side 

 have almost the same shape; the external one, thick, short, and conical, obliquely 

 erect; the internal one, a little more obtuse. Between these two papillae there is on 

 a higher level another papilla which is thinner, conical, and pointed. 



The upper brachial plates are small and narrow, somewhat longer than wide 

 at the basis of the arms, with a narrow proximal margin, a strongly convex distal 

 margin, and lateral borders, divergent and rounded. These plates afterwards 

 become almost as long as wide; they are all in contact. 



The first under brachial plate is very small, strongly narrowed in its distal 

 region between the extremities of the adjacent adoral plates which lie very close 



