OPHIURANS OF THE PHILIPPINE AND ADJACENT WATERS. 165 



concave; they are narrowed inwardly and do not reach the median 

 interradial line; but outwardly they are much broadened and sepa- 

 rate the mouth shield from the first side arm plate. The oral plates 

 are high, twice as high as broad. The proximal mouth papilla is not 

 very large; it is rectangular, with the oral border a little broadened; 

 the second, a little smaller, is conical, rather thick, with the tip trun- 

 cated; the external papilla, which is inserted both on the oral and 

 on the adoral plate, is broadened, and twice as broad as long; its 

 proximal border is markedly larger than the distal border; this 

 gives it a form resembling a triangle of which the apex is slightly 

 produced. 



The upper arm plates are large, and they cover a large proportion 

 of the dorsal surface of the arms. They are almost semicircular, 

 with the proximal border very regularly rounded, and the distal 

 border almost straight; the lateral angles are also rounded. They 

 are half again as long as broad, and are separated by a narrow in- 

 terval occupied by the side arm plates. 



The first under arm plate is triangular, with the distal border 

 straight and the lateral angles much rounded. The following plates 

 are pentagonal, almost as long as broad, with an obtuse proximal 

 angle bordered by two straight sides, the lateral borders straight or 

 slightly notched by the tentacle scale, and the distal side excavated 

 in the middle. All these plates are in contact. 



The rather strongly projecting side arm plates bear three subequal 

 conical spines with the point blunted, of which the length almost 

 reaches that of the segment. 



The single tentacle scale, which is of medium size, is slightly elon- 

 gated, with the tip rounded. 



The color of the specimen in alcohol is white. 



Affinities and distinctive features. — The species of AmpMpholis 

 having only a single tentacle scale are not numerous. A. vitax 

 Koehler, which the Siboga collected in the Sunda Archipelago, be- 

 longs to this category, but it possesses many arm spines and a very 

 different arrangement of the mouth plates; our species can not be 

 confused with it. 



AMPHIPHOLIS MISERA (Koehler). 



Plate 70, figs. 4-8. 



Amphiura miscra Kcehler ('99), pi. 8, figs. 61-65. 

 Amphipholis misera H. L. Clark ('15), p. 243. 

 Localities. — Albatross station 5100; China Sea, off southern Luzon; 

 Corregidor Light bearing N. 16° E., 10.56 kilometers (5.7 miles) dis- 

 tant (lat. 14° 17' 15" N., long. 120° 32' 40" E.) ; 64 meters (35 

 fathoms) ; January 2, 1908; gy. S. 

 One specimen (Cat. No. 41302, U.S.N.M.). 



