250 BULLETIN 75^ UNITED STATES NATIONAL MUSEUM. 



the three distalmost are long, flat, pointed spines, serving as oral 

 tentacle scales; remaining six or seven, small, narrow, and sharp. 

 (The contrast between the inner and outer oral papillae, is not quite so 

 abrupt as appears in fig. 121 &.) First under arm plate small, tliimble- 

 shaped, longer than wide; succeeding plates hexagonal or heptagonal, 

 longer than wide, more or less in contact. (The change in form in 

 the under arm plates in fig. 1216, by which they become wider than 

 long, is a mistake.) Side arm plates moderate, meeting narrowly or 

 not at all above, and not at all below; each plate carries four flat- 

 tened, hollow, fragile, bluntly pointed arm spines, of which the 

 uppermost is longest and nearly equals two joints. Tentacle pores 

 large, each one protected by three or four sharp, spiniform scales, of 

 wluch one is on the under, the others on the side, arm plate. Color 

 (dried from alcohol), disk grayish, arms and oral surface dirty 

 whitish. 



Locality. — Albatross station 5079, off Omai Saki Light, lat. 34° 15' 

 N. ; long. 138° E., 475 to 505 fathoms, pebbles, bottom temperature 

 39.1°, 1 specimen. 



Type.— Cat. No. 25672, U.S.N.M., from station 5079. 



It is unfortunate that only a single specimen of this interesting 

 species is in the collection. It will not go into any of Verrill's sub- 

 divisions of OpMacantlia, nor into any of the related genera. 



OPHIURASES, new genus.a 



Disk composed of five radial wedge-shaped divisions, each of which 

 is covered by a pair of large radial sliields, the primary radial plate 

 and two or three high rounded granules between the radial shields; 

 the primary central and interradial plates are also well marked. 

 Mouth parts and arms much as in Ophiolebes. 



Type-species. — OpMoceramis ( ?) ohstricta Lyman. 



That Lyman was in doubt as to the true relationships of this 

 species is evident from the question mark with wliich he wrote the 

 generic name. It seems to me that its relationships are with Ophio- 

 lebes, rather than with the Ophiolepididse, for it agrees with that 

 genus in its habits and arm structure very closely. But the differ- 

 ence in the disk is so marked, a new genus seems to be necessary. 

 Koehler's OpTiiogyptis is, I think, nearly related, but the under sur- 

 face of the arms in that genus is quite different. 



OPHIURASES OBSTRICTUS. 



OpMoceramis (?) ohstricta Lyman, Bull. Mus. Comp. Zool., vol. 5, 1878, p. 124. 



Localities.— Albatross station 4890, Eastern Sea, lat. 32° 26' 30" 

 N.; long. 128° 36' 30" E., 135 fathoms, rocky, bottom temperature 



« '0(j):dupa and arjg, signifying moth, in reference to the fanciful resemblance to 

 a thick-bodied moth at rest, of the radial wedges which compose the disk (fig. 122a). 



