OPHIURANS OF THE PHILIPPINE AND ADJACENT WATERS. 61 



the broadened outer mouth papilla, should be referred to the species 

 originally called O. meridionalis by Lyman, to which H. L. Clark 

 has proposed to give the name O. mesembria, as I have stated above 

 in discussing 0. composita. 



OPHIACANTHA SEVERA, new specie*. 



Plate 17, figs. 1-3. 



Localities. Albatross station 5629 ; Patiente Strait and southward ; 

 Doworra Island (S.) bearing S. 62 W., 11.1 kilometers (6 miles) 

 distant (lat. 50' 00" S., long. 128 12' 00" E.) ; 375 meters (205 

 fathoms) ; December 2, 1909 ; co. S. 



One specimen (Cat. No. 41238, U.S.N.M.). 



Albatross station 5645; Buton Strait; North Island (NE.) bearing 

 S. 10 W., 2.96 kilometers (1.6 miles) distant (lat. 5 29' 06" S., long. 

 122 36' 06" E.) ; 377 meters (206 fathoms) ; December 16, 1909. 



One specimen (Cat. No. 41237, U.S.N.M.). 



Description. The two specimens are incomplete. In that from 

 station 5629 the diameter of the disk is 5.5 mm. ; three arms are pre- 

 served for a fairly large part of their length, the fourth, which is 

 detached, is preserved in part, and the fifth is broken off close to 

 the base; the length of the arms must have been between 20 mm. 

 and 25 mm. The specimen from station 5645 is smaller; the 

 diameter of the disk does not exceed 4 mm. ; only two arms are pre- 

 served, and these are incomplete. 



I shall describe the species with special reference to the specimen 

 from station 5629, which is the larger and which is represented in 

 figures 1-3 on plate 17. 



The disk is rounded. The dorsal surface is covered by thin and 

 transparent very small rounded plates, each of which bears a club- 

 spine which is very broad at the base thence tapering rapidly to a 

 small, cylindrical, rather short column which again broadens at its 

 tip to bear a half dozen short conical, pointed, subequal and diver- 

 gent spinules. All of the club-spines are of almost the same length, 

 and their spinules also show very great regularity in their arrange- 

 ment. The result is therefore that when the dorsal surface is seen 

 from above the general appearance of these club-spines forcibly 

 brings to mind the uniform aspect which they present in Ophiothrix 

 stelligera. The club-spines of the central region of the disk are a 

 little smaller and finer than the others. When they are viewed in 

 profile there can be made out on their columns one or two small and 

 more or less developed teeth. In the specimen from station 5645 

 these club-spines are more elongated, and they resemble small true 

 spines ; their terminal spinules are less numerous and less regular than 

 in the first specimen, and they show on their cylindrical columns a 



