OPHIURANS OF THE PHILIPPINE AND ADJACENT WATERS. 23 



for a length of 60 mm. ; it could not have been very much longer ; the 

 four others are broken off at variable distances from the base. The 

 arms are rather slender, and cylindrical ; they appear rather stiffened, 

 and are only very slightly bent. 



The disk is pentagonal with the sides straight or gently convex; 

 the dorsal surface is flattened, and the ventral surface is moderately 

 convex. 



The dorsal surface of the disk is covered uniformly with a thick 

 and opaque integument, brown in color, from which arise isolated 

 short, conical, sharply pointed spines irregularly arranged, rather 

 widely separated from each other, but becoming closer together near 

 the periphery. There is not the slightest trace of radial shields. 



The ventral surface of the disk is covered with an integument 

 thinner than that of the dorsal surface, beneath which may be dis- 

 tinguished, though with some difficulty, imbricated rounded plates 

 rather close together. This surface carries spines similar to those 

 of the dorsal surface but less numerous, and not reaching to the 

 mouth shields. 



The genital slits are rather broad and much elongated, extending 

 from the mouth shields nearly to the periphery of the disk. 



The mouth shields are rather large, much broadened transversely, 

 twice as broad as long, triangular, with a very blunt and rounded 

 proximal angle and gently convex sides passing over very rounded 

 angles and uniting on the distal border, which is similarly convex; 

 this border bears in the middle a rounded lobe, which is rather broad, 

 but low. The adoral plates are large, rather narrow and elongated, 

 four times as long as broad, with the longer edges parallel; they 

 give off outwardly a narrow process which separates the mouth 

 shield from the first side arm plate. The oral plates are rather 

 large, triangular, twice as high as broad. The mouth papillae 

 number five or six on each side and are elongated and conical, with 

 the point blunted, except for the outermost, which is more broadened. 

 The unpaired terminal papilla is broad and thick with the end 

 blunted. 



The upper arm plates are quite indistinguishable, but the integu- 

 ment of the dorsal surface of the arms shows on the seven or eight 

 lowest arm segments little spines similar to those on the dorsal 

 surface of the disk of which they are a continuation; these spines 

 gradually diminish in size, and finally disappear altogether. 



The first under arm plate is triangular, with a very obtuse proxi- 

 mal angle and a very strongly convex distal border, broader than 

 long. The following plates, of average dimensions, are a little longer 

 than broad, with the distal border strongly notched in the middle 

 and a very rounded proximal angle; their sides are gently convex 



