NORTH PACIFIC OPHIURANS IN NATIONAL MUSEUM — CLARK. 67 



Localities. —Albatross station 3698, off Honshu Island, Japan, 153 

 fathoms, green mud, volcanic ashes, sand, 2 specimens; station 4957, 

 Inland Sea, lat. 32° 36' N,; long. 132° 23' E., 437 fathoms, green- 

 brown mud, fine gray sand, foraminifera, bottom temperature 39.8°, 

 4 specimens; station 4959, Inland Sea, lat. 32° 36' 30" N.; long, 

 132° 23' 20" E., 405 to 578 fathoms, green-brown mud, fine gray 

 sand, foraminifera, 1 specimen; station 5057, Suruga Gulf, lat. 34° 

 58' 40" N.; long. 138° 34' E., 270 fathoms, gray mud, bottom tem- 

 perature 44.8°, 1 specimen. Bathymetrical range, 153 to 578 fath- 

 oms. Temperature range, 44.8° to 39.8°. Eight specimens. 



Type.— Cat. No. 25545, U.S.N.M., from station 3698. 



This species is easily distinguished by its unique arm comb. While 

 Ophioglypha clemens Koehler and 0. jejuna Lyman also have a con- 

 tinuous arm comb, the disk covering of the former species and the 

 arm joints, arm spines, and upper arm plates of the latter are so 

 different from what is found in monostcecha that the three species 

 can not possibly be confused. In the type and the specimen from 

 station 5057 the side arm plates are minutely tuberculated, while in 

 the other specimens they are perfectly smooth; it is these latter speci- 

 mens also which have the oral tentacle pores separated from the 

 mouth slits, and the oral papillae very short, wide, and truncate. 

 These differences can hardly be magnified, however, into distinctions 

 of any systematic importance. 



OPHIURA CALYPTOLEPIS, new species." 



Disk 13 mm. in diameter; arms about 35 to 40 mm. long. Disk 

 covered by rather coarse thick scales, which are more or less con- 

 cealed by a delicate, very finely granular skin; a large interradial 

 marginal scale is prominent, and in the youngest specimen the pri- 

 mary plates can easily be made out. Radial shields somewhat 

 swollen, a little longer than wide, distinctly separated from each other. 

 Basal upper arm plates oblong, much wider than long, followed by 

 pentagonal or tetragonal plates, which rapidly become triangular 

 with a sharp, proximal angle; the first five to nine in contact with 

 each other. Interbrachial spaces below covered by partly concealed 

 plates, like those of the disk. Oral shields wider than long or longer 

 than wide, somewhat pentangular, the lateral margins more or less 

 concave. Ad oral plates long and narrow; oral plates shorter and 

 wider. Oral papillae, five or six on each side, wide and truncate dis- 

 tally, but becoming longer and pointed at apex of jaw. Genital slits 

 not conspicuous. Genital scales hidden by scaling of interbrachial 

 areas, their marginal papillte few and small, so that no arm cond) or 

 at most only a small and inconspicuous one is visible from above. 



a KaXunxbc, signifying covered, and hncc, signifying scale, in reference to the more or 

 less concealed scaling of the disk. 



