232 BULLETIN OF THE 



Ophiopsamrnium Semperi sp. nov. 



Plate IV., Figs. 11- 17. 



Special Marks. — Six or seven stumpy arm-spines, of which the lowest is 

 flattened and hooked : two or three little spines on the edge of the disk in 

 the interbraehial space : granulation of upper surface fine and even ; finer 

 on the disk. 



Description of an Individual. — Diameter of disk G.5 nun. Length of arm 

 2:5 mm. Width of arm, without spines, 1.7 nun. Mouth-shields small, 

 rounded, broader than lung, much obscured by being closely soldered with 

 surrounding parts and covered by thick .-kin. Tooth-pa] >ilhc about twenty- 

 five, (if nearly equal size and length, crowded into a short oval (dump. Teeth 

 three: the uppermost longest, the lowest touching the mouth-pnpilhe. Under 

 surface, and part of the sides, of arms, covered by smooth skin, through 

 which may be obscurely seen the outlines of the under arm-plates, which, 

 near base of arm, are wide, short triangles with the apex inward ; and, near 

 point of arm, have an angular heart-shape. Side arm-plates covered with 

 thick skin, and forming a well-marked crest, at right angles to the arm, con- 

 spicuous from below, hut little projecting as seen from above. I pper side 

 of arm densely covered by a granulation, of about fourteen grains in the 

 length of a mm. This granulation descends partly down the side of arm. 

 The terminal joints are naked, with a minute rudimentary tipper arm-plate : 

 those which follow have a few scattered grains, and these grow soon into a 

 continuous stratum. Disk, below and on. sides, covered with smooth skin; 

 above, with a continuous granulation, finer than that of arms: on edge of 

 disk between the arms, a pair of sharp spines, about .0 mm. long. Genital 

 scales wide, with their outer edge showing on each side of the arm. Arm- 

 spines, near disk, usually sevon ; short, stout, blunt, minutely thorny, often 

 much swelled at the base; the lowest one flattened and armed on one edge 

 with a double hook, the next one or two also flattened. Length of third and 

 longest spine .8 mm.: length of lowest and shortest .4 mm. At tip of arm, 

 three spines, of which the upper is smallest and pointed; the second pointed 

 or forked : and the third is a sharp double hook. The Ion-' tentacles, of an 

 elongated club-shape, issue from the side of the arm just below, and in front 

 of, the middle arm-spine; there is no tentacle-scale. Color, in alcohol, of 

 arms, straw yellow : disk more gray. 



A younger specimen had a disk of 4.5 mm., and arms of lfi mm.; there 

 were only six arm-spines. 



This singular species has rather flat and little tapering arms, which have 

 a tendency to roll on themselves, as in Ojihiuchondrus. 



Philippines ; C. Semper. 



