NORTH PACIFIC OPHIURANS IN NATIONAL MUSEUM CLARK. 191 



Localities. Albatross station 3338, off Alaska, lat. 54 19' X.; long. 

 159 40' W., 625 fathoms, green mud, sand, bottom temperature 

 37.3, 13 specimens; station 4765, off Aleutian Islands, lat. 53 12' 

 N.; long. 171 37' W., 1,217 fathoms, fine black sand, bottom temper- 

 ature 35.2, 32 specimens; station 4781, Bering Sea, lat. 52 14' 30" 

 N.; long. 174 13' E., 482 fathoms, fine gray sand, pebbles, bottom 

 temperature 38.6, 1 specimen; station 4803, off Kurile Islands, lat. 

 46 42' N.; long. 151 45' E., 229 fathoms, coarse pebbles, black sand, 

 bottom temperature 37, 1 specimen. Bathymetrical range, 229 to 

 1,217 fathoms. Temperature range, 38.6 to 35.2. 



Type. Cut. No. 25648, U.S.N.M., from station'4781 . 



This pretty little ophiuran differs so much from the other species of 

 OpMomitra in the shape of the radial shields and the spines of the 

 disk that it may perhaps more properly be placed in a separate genus. 

 But in the present state of our knowledge of the Ophiohelidse and 

 Ophiacanthidse, I do not think it desirable to make new genera, if it 

 can be avoided. 



OPHIOCAMAX LITHOSORA, new species.^ 



Disk 17 mm. in diameter; arms about 125 mm. long. Disk rather 

 high, with a vertical diameter of about 6 mm., divided into five wedge- 

 shaped areas by deep interradial sulci, covered by a coat of numerous, 

 small, irregular scales, the largest of which are on the interradial 

 sides of the distal ends of the radial shields; many disk scales carry 

 each a low cylindrical stump with two to six minute teeth near the 

 apex. Radial shields long, narrow, separated, more or less sunken 

 among the disk scales. Upper arm plates pentagonal, much wider 

 than long, with a proximal angle and a nearly straight distal margin; 

 only two or three at base of arm in contact. Interbrachial spaces 

 below somewhat heart-shaped; covered with small scales. Genital 

 slits conspicuous. Oral shields very much wider than long, with a 

 proximal angle, but broadly convex or nearly straight distally. 

 Adoral plates large, about as wide at outer end as at inner, where they 

 meet; oral plates indistinct. Oral papillae numerous and irregular, 

 ten or fifteen on a side; those near apex of jaw are longer and more 

 pointed than the distal ones, which are rounded and crowded together, 

 and look somewhat like little heaps of pebbles. First under arm 

 plate squarish; succeeding plates tetragonal, very much wider than 

 long; second plate has proximal margin much shorter than distal 

 and is in contact with first; remaining plates, widely separated. 

 Side arm plates rather large, meeting below and above; each plate 

 carries six or seven long, slender spines, the upper ones smooth, the 

 lower, more or less thorny; uppermost spine, or next- one, longest, 



f, signifying stone, and aiopbc, signifying limp, in rclVivncf t<> the appear- 

 ance of the distal clusters of oral papilla}. 



