KEPORT ON THE OPHIUROIDEA. Ill 



Oiohioi^holis jciponica, Lym. (PI. XXIII. figs. 13-15). 



OpTdopholis japonica, Lym., Bull. Mus. Comp. Zool., vol. vi., part 2, p. 42, pi. xiii. figs. 

 374-376, 1879. 



Upper disk covered with thin scales and large radial shields, neither of which have 

 grains or spines, except the marginal scales. Five stout, cylindrical, tapering arm spines. 



(Type specimen from Station 236.) Diameter of disk 10 mm. Length of arm about 

 40 mm. Width of arm without spines near disk 27 mm. Three or four small, irregular, 

 flat, scale- like mouth papillae on each side, and a flat clump of short, bead-like tooth 

 papillae at apex of mouth angle. Mouth shields and side mouth shields somewhat obscured 

 by thick skin. The former are transverse oval, much wider than long ; length to breadth 

 •8 : r3. Side mouth shields small and short, with rounded ends, rather wider within 

 than without, and somewhat bent. Under arm plates a little wider than long, slightly 

 separated, and with rounded corners. Side arm plates closely soldered with their neigh- 

 bours, meeting neither above nor below, rising laterally in a strong spine ridge. Upper 

 arm plates transverse oval, twice as broad as long, slightly swollen, each surrounded by a 

 single line of rounded granules, which are broader than long. Disk round and thick, with 

 a flat top, covered with thin, variously-shaped scales, which, near the margin, are obscured 

 by thick skin ; those of the centre small, round, and arranged in a rosette ; those farther 

 out, larger and elongated, arranged in three or four rows between the radial shields in the 

 interbrachial spaces, where they are beset with a few scattered grains, which at the margin 

 become much more numerous and larger, and appear as very short spines. Interbrachial 

 spaces below covered with a few grain- like spines. Radial shields large, pear-seed shaped, 

 much longer than wide, separated usually by a line of two large and two small scales. 

 Genital openings large and extending about two-thirds the distance to the margin. Five, 

 rarely six, stout cylindrical, blunt, tapering arm spines, whereof the second and third are 

 stoutest, and as long as one and a half arm joints. One, and on the first two joints 

 sometimes two, small, rounded tentacle scales. At tip of arm are four slender spines, of 

 which the lowest takes the form of a flat, long, three toothed hook, as elsewhere in this 

 genus. Colour in alcohol, above, light pink ; below, pale straw. 



It is evident that Ophiolepis mirahilis^ Duncan, is a true Ophiopliolis, lacking none 

 of its characters, and standing c[uite near the typical Opliiopholis aculeata. The fact 

 that certain small scales surround larger ones is not here of generic importance, and 

 probably results from the young stage of the specimen, which, to judge from the 

 figures, had a disk not exceeding 4 mm, in diameter. Ophiopliolis japonica differs 

 from the old species as well as from Ophiopliolis mirahilis in its more slender arm spines, 

 and in having the radial shields and much of the upper disk free of grains or spines. 



Station 235.— June 4, 1875; lat. 34° 7' N., long. 138° 0' E. ; 565 fathoms; mud. 

 Station 236.— June 5, 1875 ; lat. 34° 58' N., long. 139° 30' E. ; 420 to 775 fathoms; mud. 



1 P. M. Duncan, Lum. Soc. Joum. Zool, vol. xiv. pp. 460 and 479. 



