80 BULLETIN 15, UNITED STATES NATIONAL MUSEUM. 



comb. First under arm plate much longer than wide, with a median 

 keel-like swelling; second plate similar, but wider, and with the keel 

 flat and broad; succeeding plates more or less elongated hexagonal, 

 ultimately becoming tetragonal and then triangular, in contact on 

 basal two-thirds of arm. Side arm plates moderate, somewhat 

 swollen, separated both above and beneath, until near tip of arm; 

 each plate bears four or five minute papilla-like arm spines, which 

 grade so closely into the tentacle scales it is diflicult to draw a line 

 between them. Oral tentacle pores opening into mouth slit, but 

 guarded on outer side by four very large scales, of which the most 

 distal is nearly or quite as large as the other three together; these scales 

 are so appressed in all the specimens, that the pore is completely 

 concealed, and one can not even see whether there are any scales on 

 the inner margin of the pore or not; the first four or five tentacle 

 pores of the arm are protected in the same way by from four to seven 

 big scales; farther out there are only four, three, or even two, much 

 smaller scales, which merge into the series of spines on each side arm 

 plate. Color (dried from alcohol), brownish-drab. 



Localities. — Albatross station 4826, off Japan, lat. 37° 25' N. ; long. 

 137° 32' E., 114 fathoins, fine gray sand, black specks, bottom tem- 

 perature 42.5°, 5 specimens; station 4828, off Japan, lat. 37 23' N. ; 

 long. 137° 36' E., 163 fathoms, green mud, bottom temperature 34.9°, 

 4 specimens. Bathymetrical range, 114 to 163 fathoms. Tempera- 

 ture range, 42.5° to 34.9°. Nine specimens. 



Type.— Cat. No. 25546, U.S.N.M., from station 4826. 



This species is quite intermediate between the species of the sarsii 

 group of OpJiiura, on the one hand, and the species of the sculptilis 

 group on the other, though it appears to be more nearly related to 

 the latter. It is easily distinguished from previously known species 

 by the coarse disk scales and wide, appressed comb papillae in com- 

 bination with the minute, l)lunt arm spines, and the big, flat tentacle 

 scales. The smallest of the specimens before me has the disk 9 mm. 

 in diameter; it has, for the most part three well-spaced arm spines, 

 and only two tentacle scales, often only one, beyond the three or 

 four basal pores. 



OPHIURA HADRA, new species.a 



Disk 32 mm. in diameter; arms probably about 100 mm. long. 

 Disk stout, flat or slightly arched, nearly 10 mm. thick, covered by 

 about seventy -five plates, among which only the radial shields are 

 conspicuously large; the plate just proximal to each pair of radial 

 shields is more or less swollen, much as in ponderosa. Radial shields 

 longer than wide, in contact except at inner end, where they diverge. 

 Arms stout, rounded and little compressed, about 7 mm. wide and 5 



o 'ASpof, signifying stout, thick, in reference to its very heavy, solid appearance. 



