MUSEUM OF COMPAKATIVE ZOOLOGY. 51 



shield well marked, of a transverse diamond-shape, with rounded corners. Side 

 mouth-shields thick and slightly swollen, rather wide, nearly or quite meeting 

 within, tapering gently inward. Under arm-plates somewhat wider than long, 

 with a wide curve without, short re-enteringly curved laterals, and straight 

 inner laterals sloping towards the median line. Side arm-plates presenting a 

 moderately prominent spine-crest. Upper arm-plates wider than long, slightly 

 overlapping, of a transverse diamond-shape, with corners rounded or truncated ; 

 each plate has a median ridge, which gives to the upper arm a carinate look. 

 Disk thick and strongly lobed in the interbrachial spaces ; its upper surface 

 occupied chiefly by large radial shields, which are long triangular, with a length 

 to breadth of 5 : 3 ; they unite without, where each has a lobe projecting over 

 the arm, separated within by a narrow wedge of scales bearing one or two rows 

 of short, slightly rough spines : similar but somewhat longer spines densely 

 clothe the centre and interbrachial spaces, passing over the margin and investing 

 the outer portion of the naked surface below ; the longest spines are 1.7 mm. 

 Ten moderately stout, scarcely sapering, somewhat flattened, translucent arm- 

 spines, bearing feeble thorns on their edges ; the uppermost and lowest are 

 minute, the rest diminish in length from the third downward ; lengths to that 

 of an under arm-plate, .8, 3.6, 4.6, 3.6, 3, 3, 2.6, 2, 1, .8 : 1. The first tentacle- 

 pore has no scales ; those beyond have a minute lip-like one in the angle of the 

 under and side arm-plates. Color in alcohol, above, pale purplish pink, the 

 side arm-plates and outer edges of radial shields marked with darker ; below, 

 much paler. 



Station 142, 150 fathoms, 12-}- specimens. Station 161 {var. with coarser 

 spines), 38 fathoms, 2 specimens. Station 163 (var.), 120 fathoms, 5 speci- 

 mens. 



The species is readily distinguished from 0. capensis by lacking the black 

 stsipe on the arm, and by having arm-spines serrated their whole length. 



Ophiothrix capillar is sp. nov. 



Plate XIV. Figs. 401 - 404. 



Special Marks. — Very large, with nine very delicate, translucent arm-spines, 

 whereof the upper ones are extremely long. Disk set with minute stumps, 

 which are few and scattered on the large radial shields. 



Description of an Individual (Station 204). — Diameter of disk 22 mm. 

 Width of arm near disk, 4.8 mm. The vertical oval has over fifty tooth-papillse 

 of various sizes, those in the lower half being minute, crowded, and grain-like, 

 while those on the margin of the upper half are large and thick, and project 

 beyond the median papillae. Four flat teeth, with rounded cutting edge ; the 

 uppermost and lowest narrowest. Mouth-shields small, much broader than 

 long, bounded' by a gentle curve without and an obtuse angle within ; length 

 to breadth .8 : 1.8. Under arm-plates small, narrow, about as long as broad, 

 eight-sided, with angles mote or less rounded and lateral sides a little re-enter- 

 ingly curved. Side arm -plates with a well-marked spine-ridge. Upper arm- 



