OPHIUKANS OF THE PHILIPPINE AND ADJACENT WATERS. 253 



(lat. 12° 38' 15" N., long. 122° 12' 30" E.) ■ 68 meters (37 fathoms) ; 

 March 25, 1908 ; hrd S. 



One specimen (Cat. No. 41018, U.S.N.M.). 



Description. — The diameter of the disk is 5 mm.; the arms are un- 

 fortunately all broken off near the base, and they are not preserved 

 for a greater length than 7 mm. 



The disk is rounded, with the two surfaces slightly convex. The 

 dorsal surface is covered between the radial shields, which are of 

 medium size, with numerous plates, of which the outlines are fairly 

 evident, and which bear both small club spines ending in divergent 

 spinules which are rather thick at the base, unequal, and often three 

 in number, and slender, sharp, and rather long true spines, provided 

 with fine denticulations, which are mixed with the club spines, and 

 are rather numerous. All intermediate stages between these spines 

 and the club spines are found, especially toward the periphery of the 

 disk. The radial shields are not very large, as I have just said, though 

 their length is a little greater than the radius of the disk ; they are 

 triangular, in contact outwardly, and separated inwardly by a row of 

 plates bearing club spines or true spines. These shields themselves 

 carry on their surface a certain number of spines mixed with club 

 spines. 



The ventral surface of the disk in its median portion is covered 

 with rounded plates, each one bearing a club spine ending in unequal 

 spinules which are shorter than those on the dorsal surface. These 

 plates reach almost to the bottom of the interradial areas, but they 

 leave naked a broad band along the genital slits. 



The mouth shields, which are of medium size, are triangular, with 

 the sides slightly excavated, and joining over a rather prominent 

 angle the apex of which is rounded: the distal border is very 

 strongly convex. The adoral plates are rather small, broadened out- 

 wardly and in contact inwardly through a narrow and rounded 

 border. The oral plates are high and strong. The tooth papillae 

 are arranged in several rows. 



The upper arm plates are large, quadrangular, a little longer than 

 broad, with a very narrow and straight proximal border and diver- 

 gent and slightly excavated sides ; the distal border is very broad and 

 very strongly convex, and it is sometimes resolved into three sides 

 which are united by very obtuse angles. All these plates are in con- 

 tact. 



The first under arm plate is rather large, broader than long, with 

 the distal border convex. The following are very large, almost as 

 long as broad, with a straight proximal border, the sides very slightly 

 excavated by the tentacle pores, and passing over very rounded 

 angles to the distal border, which is slightly convex. They are all 

 in contact. 



