OPHIURANS OF THE PHILIPPINE AND ADJACENT WATERS. 63 



sponding under arm plate; its surface is covered with asperities 

 which are especially marked toward the tip, and which make it 

 slightly spiniferous. 



The color of the specimen in alcohol is yellowish white. 



Affinities and distinctive features. — Ophiacantha severa seems to 

 me to be closely related to O. serrata Lyman, but it is difficult to form 

 an exact idea of the latter species from Lyman's description and 

 figures. I requested Prof. F. Jeffrey Bell to compare the photo- 

 graphs of my ophiuran with the Challenger species O. serrata, as he 

 had done in the case of O. longidens. The opinion of the learned 

 naturalist of the British Museum is that the two species are different. 

 The new species differs from O. serrata in its lozenge-shaped mouth 

 shields, which are scarcely broader than long; in the large and 

 strong tentacle scale which is furnished with rather strong asperities 

 and in no way spiniform; in the armature of the dorsal surface of 

 the disk which consists of elongated club-spines terminated by 

 numerous spinules, and which may even become elongated to the 

 point of resembling small true spines, while in O. serrata Lyman 

 notes only " minute grains like stumps bearing a crown of blunt 

 thorns " ; and finally in the very large under arm plates, the surface 

 of which shows very marked concentric striations, which, moreover, 

 are found also on the other arm plates. 



OPHIACANTHA VORAX Kcehler. 



Plate 15, figs. 4, 5. 



Ophiacantha vorax Kcehler ('96), p. 353, pi. 8, figs. 68, 69; ('99), p. 62, 



pi. 7, figs. 52-54.— H. L. Clark ('15), p. 208. 

 Ophiacantha anchUabra H. L. Clark ('11), p. 205, fig. 95; ('15), p. 196. 



Local "it i/. — Albatross station 5606; Gulf of Tomini, Celebes; 

 Dodepo Island (W.) bearing N. 3° W., 20.01 kilometers (10.8 miles) 

 distant (lat. 0° 16' 28" N., long. 121° 33' 30" E.) ; 1,525 meters 

 (834 fathoms) ; November 17, 1909; gn. M. 



One specimen (Cat. No. 41142, U.S.N.M.). 



Notes. — The specimen is in fairly good condition, and almost all 

 the arms are preserved for their whole length; the diameter of the 

 disk is 7 mm., and the length of the arms is more than 45 mm. 



This individual is a little larger than those which served me as the 

 type series upon which I established the species and which were 

 collected by the Investigator off Cape Comorin in 1,908 meters (1,043 

 fathoms). It agrees well with these except for insignificant varia- 

 tions; for example, the tentacle scale, always very large and broad, 

 is perhaps a little less pointed than in the Investigator specimen, and 

 the arm spines are also somewhat less denticulated, and often smooth, 

 especially the dorsal ones. 



