NORTH PACIFIC OPHIURANS IN NATIONAL MUSEUM CLARK. Ill 



shells, bottom temperature 49.4, 4 specimens; station 5069, Suruga 

 Gulf, lat. 35 3' 10" N.; long. 138 47' E., 108 to 131 fathoms, mud, 

 sand, broken shells, bottom temperature 55.8, 2 specimens; station 

 5091, Uraga Strait, lat. 35 4' 10" N.; long. 139 38' 12" E., 197 

 fathoms, green mud, coarse black sand, pebbles, bottom tempera- 

 ture 47.6, 7 specimens; station 5092, Uraga Strait, lat. 35 4_' 50" 

 N.; long. 139 38' 18" E., 70 fathoms, coarse black sand, bottom 

 temperature 56.3, 2 specimens; station 5093, Uraga Strait, lat. 

 35 3' 15" N.; long. 139 37' 42" E., 302 fathoms, coarse black 

 sand, bottom temperature 43.9, 1 specimen; station 5094, Uraga 

 Strait, lat. 35 4' 42" N.; long. 139 38' 20" E., 88 fathoms, black 

 sand, broken shells, bottom temperature 54.8, 16 specimens. Bathy- 

 metrical range, 70 to 578 fathoms. Temperature range, 56.3 to 

 43.9. Thirty-six specimens. 



Type. Cat. No. 25646, U.S.N.M., from station 5069. 



The smallest specimen has the disk 7 mm. in diameter. It differs 

 from the large ones in having fewer, less swollen, but more tuber- 

 culous disk scales, radial shields in contact near middle, only one 

 or three scales in interbrachial space distal to oral shield, and only 

 three or four arm spines. The growth changes, therefore, are the 

 same in this species as in simplex, which is apparently the nearest 

 ally of trychnum, but from which it is easily distinguished by the 

 persistence of the under arm plates, the much rougher disk and the 

 number of arm spines. I know of no other species with which 

 trychnum is likely to be confused. 



OPHIOMUSIUM JOLLIENSIS. 



Ophiomusium jolliensis MCCLENDON, Univ. of California Publ., Zool., vol. 6, 1909, 

 no. 3, p. 36. 



Disk 21 mm. in diameter; arms 50 to 55 mm. long. Disk rela- 

 tively thin and flat, covered with numerous scales, among which 

 only a big marginal plate in each interradius and the radial shields 

 are prominent. Radial shields much longer than wide, well sep- 

 arated. Distal to each radial shield, on side of base of arm, are 

 numerous coarse, granule-like scales. First two or three upper arm 

 plates decidedly wider than long, but succeeding plates are longer 

 than wide ; at first rounded pentagonal, but soon becoming diamond- 

 shape. Near tip of arm the plates are very minute, nearly trian- 

 gular, and about as wide as long; only first three to six in contact. 

 Interbrachial spaces below covered by numerous scales, of which a 

 median series and those near margin are somewhat larger than 

 others. Oral shields small, much longer than wide, narrower dis- 

 tally than proximally. Adoral plates short and wide, lying beside, 

 instead of proximal to, oral shield ; oral plates small. Oral papillae 

 small, six to seven on a side, outermost largest; an odd one at 



