NORTH PACIFIC OPHIURANS IN NATIONAL MUSEUM CLARK. 143 



fathoms, mud, bottom temperature 36.8, 113 specimens; station 

 4761, off Alaska, lat. 53 57' 30" N.; long. 159 31' W., 1,973 fathoms, 

 blue clay, bottom temperature 35, 3 specimens; station 4766, Bering 

 Sea, lat. 52 38' N.; long. 174 49' W., 1,766 fathoms, bottom tem- 

 perature ? (about 35), 13 specimens; station 5087, Sagami Bay, lat. 

 35 9' 40" N.; long. 139 19' 5" E., 614 fathoms, green mud, bottom 

 temperature 37.5, 1 specimen; locality ?, 21 specimens. Bathymet- 

 rical range, 60 to 1,973 fathoms. Temperature range, 42.8 to 35. 

 One hundred and sixty-two specimens. 



Type. Cat. No. 25594, U.S.N.M., from station 2859. 



This species will be easily recognized by the combination of naked 

 interbrachial spaces, long radial shields, one tentacle scale, three arm 



FIG. 50. AMPHIURA LEPTODOMA. 



X 15. a, FROM ABOVE; b, FROM BELOW; c, SIDE VIEW OF TWO ARM 



JOINTS NEAR DISK. 



spines, and spine-like outer, oral papillae. The specimens range in 

 size from less than 3 mm. disk diameter to a full 8 mm. No differ- 

 ences were detected between the specimens from 60 fathoms and those 

 from 1,973. It is interesting to note that in spite of this great bathy- 

 metrical range, the temperature range is less than 8 and the bottom 

 at all the stations was soft, without rocks or shells. 



AMPHIURA LEPTODOMA, new species.a 



Disk a little more than 3 mm. in diameter; arms about 25 mm. 

 long. Disk covered by numerous (300 to 400) small scales. Radial 

 shields large, about twice as long as wide, separated, except at distal 

 ends. First upper arm plate twice as wide as long, elliptical; suc- 

 ceeding plates broadly oval, wider than long, scarcely in contact. 



a AsTZTodouof, signifying slightly built, in reference to the general appearance. 



