MUSEUM OF COMPARATIVE ZOOLOGY. 53 



strong thorns on their edges ; the second one is longest, and those below grow 

 gradually shorter ; lengths to that of an under arm-plate, 2.3, 3.5, 2.5, 2.2, 1.7, 

 1.5, .7 : .7. One minute tentacle-scale. Color in alcohol, above, disk pale 

 greenish gray, arms of a faint pink. 



Station 192, 129 fathoms, 1 specimen. Station, Cebu, Philippines, 95-100 

 fathoms, 1 specimen. 



Ophiothrix caespitosa sp. nov. 



Plate XV. Figs. 417-420. 



Special Marks. — Nine short, stout, much flattened, strongly toothed arm- 

 spines. The puffed disk and small radial shields are set with short spines. 

 Upper arm-plates transverse diamond-shaped, with lateral angles sharp. 

 • Description of an Individual (Port Jackson). — Diameter of disk 7 mm. 

 Length of arm 28 mm. Width of arm near disk 1.5. The vertical oval has 

 about sixteen stout, blunt, nearly equal tooth-papillae, whereof four or five are 

 on the median line, and nearly as large as those on the margin. Four rather 

 thin, squarish teeth, with a cutting edge making an obtuse angle. Mouth- 

 shields small, closely joined to surrounding parts, broader than long, of a trans- 

 verse, rounded oval shape, having a curve without and a very blunt, obtuse angle 

 within. Side mouth-shields narrow, wider without than within, where they 

 meet. Under arm-plates with ill-marked outlines of a rude, transverse oval 

 form, with a curve without, lateral sides a little indented and the inner side 

 vaguely angular. Side arm-plates with a low spine ridge. Upper arm-plates 

 much wider than long, transverse diamond-shape, with lateral angles sharp and 

 the outer one rounded ; length to breadth .5 : 1.1. Disk thick, and pufted in 

 the interbrachial spaces, thickly set near the margin with short, stout, stump- 

 like spines rough at ends and sides, the longest .5 mm. in length. Towards the 

 centre the spines grow fewer, and the middle region has scarcely any, so that 

 the rounded overlapping scaling is conspicuous ; next the mouth-shields, also, 

 there are no spines. Radial shields small and triangular, much obscured by 

 the short spines. Nine short, translucent, rather stout, blunt, flattened arm- 

 spines, bearing pretty strong thorns on their edges ; lengths to that of an under 

 arm-plate, .8, 1.5, 1.8, 1.7, 1.3, 1.1, .9, .7, .4 : .5. One minute tentacle-scale at 

 angle of under and side arm-plates. Color in alcohol, above, disk faint green- 

 ish ; arms banded with lighter and darker yellowish brown. 

 Station, Port Jackson, 2-10 fathoms, 3 specimens. 



In its disk this species resembles O. iriglochis, but the arm-spines are much 

 flatter and more toothed, and the upper arm-plates of a diff'erent shape. 



Ophiothrix violacea Mijll. & Trosch. 



Ophiothrix violacea. Syst. Asterid., p. 115. 



Off Brazil, 7-20 fathoms, 12-f specimens. Station 36, off Bermuda, 32 

 fathoms, 3 specimens. Fernando Noronha (same species ?), shallow water, 

 1 specimen. 



