NORTH PACIFIC OPHIURANS IN NATIONAL MUSEUM CLARK. 179 



This very handsome ophiuran seems to be quite distinct from any 

 of the three species upon which Krehler based the genus, though it 

 is obviously congeneric with them. Aside from its pretty coloration, 

 it may be easily recognized by the very small adoral plates, the long, 

 pointed oral shields, the wide upper arm plates and the small, widely 

 separated radial shields. It seems to be nearest to 0. malignus 

 Koehler, but the differences in the shape of the disk, of the oral shields, 

 of the radial shields, and of the upper arm plates are very marked. 



Family OPHIOHELUXE." 



OPHIOMITRA CARDIOMORPHA, new species, ft 



Disk 14 mm. in diameter; arms' about 90 mm. long. Disk divided 

 into five wedge-shaped divisions by deep interradial sulci; each divi- 

 sion is covered by a pair of large, naked, radial shields and a number 

 of irregular plates; of these plates those at center of disk are the 

 smallest, but many of them carry spines 2 mm. or more in length, 

 with rough tips; the marginal disk plates are entirely without spines 

 but plates next to the radial shields often carry spines. Radial shields 

 very large, roughly triangular, nearly twice as wide as long, separated 

 for their entire length. Upper arm plates nearly twice as wide as 

 long, the distal margin slightly convex or straight, the proximal 

 strongly convex; basal ones slightly overlapping, though scarcely in 

 contact, but on the greater part of the arm they are separated. 

 Interbrachial areas below heart-shaped, covered with irregular smooth 

 scales. Genital slits very conspicuous. Oral shield diamond-shaped, 

 about as wide as long. Adoral plates large, wider without than 

 within ; oral plates small and indistinct. Oral papillae five on a side, 

 with an infradental one at apex of jaw; all but the last and penulti- 

 mate, distinctly pointed. First under arm plate small, somewhat 

 triangular; succeeding plates much wider than long, with the straight 

 or angular distal margin longer than the proximal, and lateral mar- 

 gins more or less concave and diverging distally; except first and 

 second, no two are in contact. Side arm plates large, meeting both 

 above and below, though not broadly; each plate carries five long, 

 slender arm spines, the uppermost longest (nearly equal to three 

 joints), sharpest and smoothest; the lowest shortest, bluntest, and 

 roughest. Tentacle scale single, large, thick, and sharp pointed. 

 Color (dried from alcohol), very light gray, nearly white. 



Localities. Albatross station 4918, Eastern Sea, lat. 30 22' N.; 

 long. 129 8' 30" E., 361 fathoms, gray sand, globigerina, broken 

 shells, bottom temperature 42.7, 1 specimen; station 4919, Eastern 

 Sea, lat. 30 34' N.; long. 129 19' 30" E., 440 fathoms, globigerina 



For remarks on this family, see under Ophiacanthidse (p. 195). 

 b Kapd'ca, signifying heart, and floppy, signifying form, in reference to the heart- 

 shaped interbrachial spaces, seen from below (see fig. 816). 



