204 BULLETIN 75, UNITED STATES NATIONAL MUSEUM. 



Radial shields completely concealed. Upper arm plates triangular, 

 nearl}" as long as wide, the basal ones more or less in contact. Inter- 

 brachial spaces below, covered with scales which are partly obscured 

 by spines, similar to those of the disk. Genital slits large. Oral 

 shields somewhat pentagonal, longer than broad, with distal end 

 narrower. Adoral plates moderate, not peculiar. Oral papillae about 

 three on a side, notably elongated, the distal one largest and some- 

 what widened at tip ; there are two small scales protecting the second 

 pair of oral pores, close to the first under arm plate ; there is a long 

 infradental papilla at apex of jaw. First under arm plate small, 

 squarish; succeeding plates more or less hexagonal, with both prox- 

 imal and distal angle somewhat rounded, rather wider than long, at 

 first barely in contact but soon becoming separated. Side arm plates 

 very large, meeting more or less above and below, each with ten or 

 eleven smooth, slender spines, of which the next to the uppermost is 

 usually the longest and may ec|ual three or four joints. Tentacle 

 scale single, long, flat, and rounded at tip or bluntly pointed. Color 

 (dried from alcohol), light brown. 



Localities. — Albatross station 3661, Gulf of Tokyo, Japan, 169 

 fathoms, mud, pebbles, bottom temperature 48°, 9 specimens; station 

 4892, Eastern Sea, lat. 32° 27' 30" N. ; long. 128° 33' E., 181 fathoms, 

 gray sand, broken shells, rocks, bottom temperature 50.2°, 1 specimen. 



Type.—Q^i. No. 25634, U.S.N.M., from station 4892. 



This species is well characterized by its mouth parts, arm spines, 

 and tentacle scales, in addition to its peculiar disk spinules. It is not 

 likely to be confused with any of the preceding. So far as can be 

 judged by the material at hand it shows little variability, except that 

 the oral shield tends to become triangular with a proximal base and 

 a distal angle. 



OPHIACANTHA ANCHILABRA, new species." 



Disk 8 mm. in diameter; arms about 35 mm. long. Disk covered 

 by short, thick stumps, crowned with spinules. Radial shields con- 

 cealed. Arms wide and little constricted between the upper arm 

 plates; width of arm at base nearly equal to one-half radius of disk. 

 Upper arm plates broadly triangular, widely separate. Interbrachial 

 spaces below covered with scales which are little obscured by the 

 stumps they carry. Oral shields much wider than long, with little or 

 no proximal angle and a broadly curved distal edge. Adoral plates 

 large, about as wide without as within, where they do not always 

 meet. Oral papillae, about three on a side and one at apex of jaw, 

 long, thick, and bluntly pointed. Genital slits short. First under 



"-"Ajx!, signifying near to, and Xa^poc, signifying voracious (Latin vorax), in refer- 

 ence to its obvious relationship to 0. vorax Kcehler. 



