OCR Text |
Show 92 ON THE COLLECTION M A D E BY H.M.S. ' PETEREL.' [Feb. 6, II. ASTERIID^E. 3. H E L I A S T E R M I C R O B R A C H I A , Xantus. III. OPHIUR^E. 4. O P H I O T H R I X SPICULATA, Leconte. 5. OPHIONEREIS ALBOMACULATA, sp.nov. (Plate XI. figs. 1-5.) Disk somewhat pentagonal, finely scaled, the scales in the region of the radial shields larger than elsewhere; radial shields very small, narrow, pointed within, not far apart, the inner sides nearly straight, outer curved, white with the outer tips blackish; oral shields shaped like a short spear-head, the point being obtuse, and towards the mouth and the handle broad and short, the madreporic shield a little larger and of a somewhat different form ; side oral shields irregularly triangular, small, situated on the sides of the orals, the outer angle touching the first very small ventral arm-plate, tbe lower end not nearly reaching to the apex of the oral shield ; mouth-papillae 6-8 on each mouth-angle, subequal, the outermost one generally the largest; arms about six times as long as the width of the disk, broadest about an inch from it, and towards it gradually attenuating ; upper plates irregularly quadrangular, the sides converging outwardly ; the outer edge is consequently narrower than the inner, and straight; the supplementary plates on each side about half as large as the central ones ; lower arm-plates square, with the angles rounded; 4 spines on about the first twelve side arm-plates, 3 on the rest; the lowest is a little the smallest, the central one the largest (2 millims. in length), the uppermost broad, compressed and truncate at the apex ; the single tentacle-scale is large and subcircular. The colour of the disk (in alcohol) dark olive, almost black, varied with white near the radial shields ; arms above of the same dark tint as the disk, with white spots at intervals of a few segments, and towards the end of the arms the plates on each side of those which are white or which are white-spotted are almost black ; lower arm-plates purplish brown, tentacle-scales a little paler; arm-spines dark olive with pale lips. Diam. of disk 13 mill.; width of the first dorsal arm-plates including the supplementary ones 2 millims., of the fifteenth 3 millims. Hab. Charles Island. This species is remarkable in having the middle portion of the rays considerably broader than the base ; the first lower arm-plate is very small, being only about one fourth the size of the next and situated between the side mouth-shields. The white spots on the upper surface of the arms are generally on the outer edges; but towards the end of the arms they meet, thus forming transverse white bands ; and on each side of them the adjoining plates are much darker than the roots of the arms, in fact almost black, thus giving a very striking variegated aspect to them. |