REPORT ON THE OPHIUROIDEA. 183 



on it. A young one had a disk 4 mm. in diameter, and arms 16 mm. long. The disk 

 grains were rough under the microscope ; the arm spines were proportionately longer, 

 and the side arm plates more prominent, than in the adult ; the outer mouth papilla was 

 larger than its neighbours. 



Station 171.— July 15, 1874; kit. 28° 33' S., long 177° 50' W. ; 600 fathoms; rock. 



Ophiacantha granulosa, Lym. (PI. XIV. figs. 7-9). 



Ophiacantha granulosa, Lym., Bull. Mm Comp. Zool., vol. v., part 7, p. 137, pi. viii. figs. 

 206-208, 1878. 



Disk evenly set with smooth grains ; outer ends of radial shields naked ; ten smooth 

 slender arm spines. 



(Type specimen from Station 201.) Diameter of disk 9 mm. Length of arm 

 42 mm. Width of arm without spines 3 mm. Seven pointed, rather stout, nearly 

 cylindrical mouth papillae Seven teeth, flat, with a rounded cutting edge. Mouth 

 shields small, broader than long, with an obtuse angle within, and a curve without ; 

 length to breadth, "8:1. Side mouth shields large and wide, broader without than 

 within, where they are slightly separated. Under arm plates much wider than long, of a 

 wide axe-shape, with a curved edge outward, a lobe or a narrow obtuse angle within, and 

 the lateral sides re-enteringly curved. Upper arm-plates rather small, of a wide fan- 

 shape, with an angle inward, and lateral sides re-enteringly curved. Side arm plates 

 large and moderately projecting, meeting broadly above, near base of arm, but scarcely 

 touching below. Disk slightly puffed, closely and evenly set with smooth grains, about 

 four in the length of a millimetre, which hide the fine disk scales, except in the lower 

 interbrachial spaces. Eadial shields covered, except their outer ends, which are naked 

 and sunken below the surrounding surface. Ten slender, tapering, cylindrical translucent 

 arm spines, which are not thorny; lengths to that of an arm joint, 3"2, 3"2, 2 - 2, 2, 2, 

 2, 1*8, 1*3, 1"3, 1 : 1. One rather small, blunt tentacle scale. Colour in alcohol, pale 

 reddish-brown. 



A younger specimen, with a disk 4 mm. in diameter and an arm of 18 mm., presented 

 no special variations, except that there were only eight arm spines, and the under arm 

 plates were proportionately smaller. 



Station 201.— October 26, 1874 ; lat. 7° 3' N., long. 121° 48' E. ; 82 to 102 fathoms; 

 stones and gravel. 



O-phiacantha valenciennesi, Lym. (PI. XXVI. figs. 7, 8). 



Ophiacantha valenciennesi, Lym., Bull. Mus. Comp. Zool., vol. vi., part 2, p. 57, pL xv. figs. 

 408-410, 1878. 



Disk evenly granulated above. Seven long, slender, much flattened arm spines. 

 Outer mouth papilla spatula-like and covering the pore of the mouth tentacle. 



