NORTH PACIFIC OPHIURANS IN NATIONAL MUSEUM CLARK. 73 



of the arm plates, the shape of the oral shields, and particularly the 

 number and arrangement of the arm spines. Usually two arm spines, 

 larger than the others and of somewhat different shape, can be quite 

 easily distinguished, one next to the tentacle scales, the other high up 

 on the arm, but either one or both of these may be wanting or at best 

 no larger than the adjoining spinelets. In some specimens the con- 

 trast between these two spines and those which accompany them, 

 is very marked, the latter being flat, thin and scale-like, while in other 

 specimens all the arm spines are reduced to minute, rounded papillae. 

 It is very often difficult to distinguish sharply between the tentacle 

 scales and the lowest arm spines. The most extreme variation is 

 shown by some of the specimens from Icy Cape (see fig. 20) in 

 which the oral shields are extraordinarily elongated and there are 

 deep transverse grooves between the basal under arm plates. The 

 arms are also high and strongly compressed, so that they are virtually 

 keeled near the base. I at first considered this form a distinct species, 

 but the connecting series is too complete to warrant its recognition. 



OPHIURA SCULPTA. * 



Ophioglypha sculpta DUNCAN, Journ. Linn. Soc. London, vol. 14, 1879, p. 455. 

 Ophiura sculpta MEISSNER, Bronn's Thierreichs, vol. 2, ser. 3, 1901, p. 925. 



Localities. Albatross station 3702, off Honshu Island, Japan, 

 31 to 41 fathoms, volcanic mud, sand, rocks, 2 specimens; station 

 4893, Eastern Sea, lat. 32 32' N.; long, 128 32' 50" E., 95 to 106 

 fathoms, gray sand, broken shells, pebbles, bottom temperature 55.9, 

 5 specimens; station 4894, Eastern Sea, lat. 32 33' N.; long. 128 

 32 ' 10" E, 95 fathoms, green sand, broken shells, pebbles, 2 speci- 

 mens; station 4895, Eastern Sea, lat. 32 33' 10" N. ; long. 128 32' 10" 

 E., 95 fathoms, green sand, broken shells, pebbles, 5 specimens; sta- 

 tion 4900, Eastern Sea, lat. 32 28' 50" N. ; long. 128 34' 40" E., 139 

 fathoms, gray sand, broken shells, bottom temperature 52.9, 1 speci- 

 men; station 4903, Eastern Sea, lat. 32 31 ' 10" N. ; long. 128 33' 20" 

 E., 107 to 139 fathoms, gray sand, broken shells, 1 specimen. Bathy- 

 metrical range, 31 to 139 fathoms. Temperature range, 55.9 to 52.9. 

 Sixteen specimens. 



These specimens answer very well to Duncan's description and 

 figures, and show very little diversity of structure among themselves. 

 The largest one is only a trifle larger than Duncan's type, having the 

 disk a little more than 8 mm. in diameter and the arms nearly 13 mm. 

 long. 



OPHIURA STUWITZII. 



Ophiura stuwitzii LUTKEN, Vid. Medd. for 1857, 1857, p. 51. 



Localities. Albatross station 2845, off Alaska, lat. 54 5' N. ; long. 

 164 9' W., 42 fathoms, coarse black sand, bottom temperature 42, 

 1 specimen; Alaska, 23 specimens; Alaska, Dall's collection, 1 speci- 

 men; Kyska Harbor, Alaska, 9 to 14 fathoms, 1 specimen. 



