156 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



spines, and the mouth shields are triangular. A. macraspis, which 

 has recently been described by H. L. Clark, has extremely small 

 radial shields, and triangular upper arm plates. 



AMPHIURA DEMISSA, new species. / 



Plate 69, figs. 1 and 2. 



Locality. Albatross station 5492; between Leyte and Mindanao; 

 Diuata Point (W.) bearing S. 45 W., 28.17 kilometers (15.2 miles) 

 distant (lat, 9 12' 45" N.. long. 125 20' 00" E.) ; 1,344 meters (735 

 fathoms) ; August 1, 1909; gy. M. 



One specimen (Cat. No. 41177, U.S.N.M.) 



Description. The diameter of the disk is 8 mm. ; the slender and 

 flattened arms are very long; the longest is preserved over a length 

 of 70 mm., and is incomplete; this arm tapers very gradually from 

 the base. The specimen is not in a good state of preservation ; there 

 are rents on the dorsal surface of the disk, and the mouth plates are 

 somewhat deformed ; nevertheless the characters are easily made out, 

 and I do not know an}^ species to which it may be assigned. 



The disk is rounded, rather strongly excavated in the interradial 

 spaces, and very gently notched above the bases of the arms. The 

 dorsal surface is covered with extremely small but very distinct 

 plates; these plates are subequal and imbricated; they become still 

 smaller at the periphery of the disk, but a little larger in the vicinity 

 of the radial shields. There is no indication of primary plates. 

 The rather small radial shields are moderately broad, a little more 

 than twice as long as broad, with the external border very convex, 

 the internal border straight, and the proximal angle rounded; the 

 two shields of each pair are in contact outwardly, and diverge from 

 that point inward. Their length is a little greater than one-third 

 the radius of the disk. 



The ventral surface is covered with plates which are a little smaller 

 than those of the dorsal surface, but nevertheless very distinct ; they 

 become a little larger in the vicinity of the mouth shields and the 

 genital slits. These last are broad and very evident. 



The mouth shields are a little broader than long, lozenge-shaped, 

 with the angles very rounded and the sides equal. The adoral plates, 

 which are of medium size, are triangular, tapering inwardly, and 

 their rounded tip does not quite reach the median interradial line; 

 they are much broadened outwardly and give off a process which 

 separates the mouth shield from the first side arm plate. The oral 

 plates are rather high. The proximal mouth papilla is of medium 

 size, somewhat elongated, with the tip rounded ; the second papilla, 

 inserted on the oral plate, is much broadened and low, rectangular, 



