OPHIURANS OF THE PHILIPPINE AND ADJACENT WATERS. 51 



The type specimen of O. duplex was discovered by the Investigator 

 oft Colombo, Ceylon, in 1,234 meters (675 fathoms). 



Under the name of Ophtacantha diploa H. L. Clark in 1911 ('11, 

 p. 207) described an ophiuran from the southern part of the Sea of 

 Japan (lat. 32° N., long. 132° E.), 799 meters (437 fathoms), which 

 differs from 0. duplex only in unimportant features. In that 

 author's type specimen the diameter of the disk is 7 mm., and the 

 arms are 45 mm. long. I believe that in spite of the differences in- 

 dicated by H. L. Clark, the two represent the same species. In the 

 Albatross specimens, which unfortunately are of small size, I count 

 eight and even nine spines at the base of the arms, and the dorsal 

 spines approach more closely the median line than in my type ; these 

 spines, as can be seen on the two photographs which I give here, are 

 provided with very distinct denticulations, while in H. L. Clark's 

 specimens they are almost smooth. I do not dare to state in a formal 

 manner that the two species are identical, but it seems to me very 

 probable. 



The two photographs which I give here will permit of more 

 ready comparisons than the figures which I published of 0. duplex 

 in 1896 and in 1899. 



OPHIACANTHA GRAPHICA, new species. 



Plate 18, figs. 4, 5. 



Locality. — Unknown. 



One specimen (Cat. No. 41233, U.S.N.M.) 



Description. — The unique specimen is very well preserved, lacking 

 only a small part of one of the arms ; it is unfortunately small ; the 

 diameter of the disk scarcely exceeds 3 mm., and the arms are 18 

 mm. long. In spite of its small dimensions it is well characterized, 

 and I do not see any species to which it may be assigned ; I therefore 

 consider it as representing a new form. 



The disk is rounded; the arms are slender, delicate, somewhat 

 moniliform, with the segments short and close together. 



The dorsal surface of the disk is covered with very closely crowded 

 slender and elongated club-spines, each terminating in three ex- 

 tremely fine and slightly divergent spinules of the same length. 

 These club-spines only leave exposed the distal portion of the radial 

 shields. The ventral surface of the disk in the interradial spaces 

 has a similar covering, but the club-spines, as well as the spinules 

 on their summits, become shorter toward the mouth shields. The 

 genital slits are broad and very evident. 



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

 rather high, broader than long, but the breadth does not exceed once 

 and a half the height; the proximal angle is obtuse, bordered by 



