MUSEUM OF COMPARATIVE ZOOLOGY. 159 



and a notch without, but are hidden by thick skin. No side or upper arm- 

 plates visible, but, on remo\'ing the skin, the latter are seen to be small trian- 

 gular, and separated by the side plates. Disk round and arched, covered by a 

 thick skin which in the centre is irregularly wrinkled. Radial shields like 

 long narrow ridges covered with a thick skin and set with small fiat grains ; 

 the brachial and interbrachial spaces have the skin more or less wrinkled, and 

 often with a few grains ; the lower interbrachial spaces have the same thick, 

 somewhat wrinkled skin. There ai'e on the first three joints three arm-spines ; 

 beyond this there are four ; they are short, stout, and microscopically thorny, • 

 with blunt points, and are covered with thick skin ; the upper spines being 

 longest. No tentacle-scales. Color in alcohol, white. 

 Station 145, 310 fathoms, 12 -|- specimens. 



Ophiolebes vestitus sp. nov. 



Plate X. Figs. 255-267. 



Special Marks. — Disk covered by thick skin and set with short stumps, or 

 grains, bearing a crown of blunt thorns. Arm-spines short, stout, opaque, 

 thorny. Mouth-papillce stout, blunt, spiniform. 



Description of an Individual (Station 308). — Diameter of disk lOmm. Length 

 of arm 50 mm. Width of arm without spines 2.3 mm. Nine mouth-papillse, 

 of which the lateral are stout, blunt, cylindrical, crowded, somewhat movable, 

 and with rough ends ; the innermost is flat and squarish, like the teeth. 

 Mouth-shields small, wider than long, with a lobe without and an obtuse angle 

 inward ; length to breadth 1 : 1.2. Side mouth-shields somewhat curved, ex- 

 tending beyond mouth-shield, wider without than within, where they meet. 

 Under arm-plates pentagonal, with a rounded angle inward. Upper arm- 

 plates fan-shaped, with a truncated angle inward. Side arm-plates meeting 

 narrowly above and below, projecting but slightly. Disk a little puffed, cov- 

 ered by thick skin, and sparsely but regularly beset with short stumps or grains 

 bearing a crown of blunt thorns. Six stout, cylindrical, blunt, thorny arm- 

 spines ; lengths to that of an arm-joint 1.8, 1.2, 1, .8, .8, .8 : .8. One small, 

 narrow, pointed tentacle-scale. Color in alcohol, white. 



A young specimen with a disk of 4 mm. had arms 10 mm. long. The disk- 

 stumps were longer, and like very short thick spines. The arm-spines were 

 less thorny. In this stage it is very near the Ophiuran described by Ljungman 

 as Opliiactis clavigera, which has the same habits also, and is doubtless the 

 young of a form of Ophiolebes, like the present one. It differs in having the 

 disk-scales and part of the radial shields naked. 



That 0. clavigera is of a novel type is shown by the fact that Ljungman 

 considered it an extreme modification of Ophiactis, while Llitken deemed it 

 nearer Ophiacantha. 



Station 307, 140 fathoms, 3 specimens. Station 308, 175 fathoms, 7 speci- 

 mens. Station 310, 400 fathoms, 1 specimen. 



