REPORT ON THE OPHIUROIDEA. 135 



separated within. First under arm plate very small and squarish ; those beyond are nearly 

 square and rather narrow, with outer corners rounded, and slight re-entering curves on 

 the lateral sides. Side arm plates wide, prominent, and much swollen along the spine 

 crest ; separated below, nearly or quite meeting above. Upper arm plates transverse 

 oval, much wider than long, with well rounded lateral ends. Disk flat and angular, 

 covered above with coarse, rounded, overlapping scales, the five primaries being but 

 little larger than the other scales ; the scaling on the interbrachial spaces is finer than 

 in the central portion. Kadial shields much longer than broad, tapering towards each 

 extremity, with the inner point acute, separated their entire length by two or three rows 

 of irregular scales ; length to breadth, 2 : 7. The scales of the margin continue round 

 the outer end of the radial shields. Interbrachial space below only about one-third 

 covered with minute scaling ; the rest of the space is naked. Four stout, blunt, tapering, 

 cylindrical arm spines, evenly spaced on the side arm plate. One stout, round tentacle 

 scale on the inner side of the tentacle pore. Colour in alcohol, disk grey, arms straw. 



Station 150.— February 2, 1874; lat. 52° 4' S., long. 71° 22' E, ; 150 fathoms; 

 rock. 



Arnphiura dilatata, Lym. (PL XXIX. figs. 4-6). 



Amplviura dilatata, Lym., Bull. Mus. Comp Zool., vol. vi., part 2, p. 26, pi. xi. figs. 

 314-316, 1879. 



Disk naked below. Eadial shields narrow pear-seed shape. Four or five small, widely 

 spaced arm spines. No tentacle scales. 



(Type specimen from Station 141.) Diameter of disk 5 mm. Length of arm 23 mm. 

 Width of same without spines, close to the disk, - 7 mm. At the base of the mouth angle, 

 on each side, is a long, very slender mouth papilla, and a pair, blunt and rounded, at the 

 apex. Mouth shields small, short diamond shape, with much rounded angles. Side 

 mouth shields small and curved, narrow within, where they nearly or quite meet ; outer 

 end wide club-shaped. Under arm plates narrow, longer than broad, squarish, with re- 

 entering curves on the lateral sides, and the outer edge nearly straight. Side arm plates 

 very small, not prominent, nearly or quite meeting above, separated below. Upper arm 

 plates transverse oval, with the inner curve stronger than the outer, and the lateral corners 

 pointed ; there is a slight longitudinal ridge. Disk rather thick and slightly puffed ; 

 primary plates widely separated and scarcely to be distinguished from the general scaling, 

 which is fine, regular and overlapping, having about ten scales in the length of 1 mm. ; 

 those of the interbrachial spaces are smallest and most closely overlapping. Radial shields 

 small, and slightly swollen, narrow pear-seed shaped, separated their entire length by a 

 narrow wedge row of scales ; a pair of short, stout scales at their outer ends. Under 

 surface of disk naked. Five short, tapering, blunt arm spines, evenly spaced on the side 



