MUSEUM OF COMPARATIVE ZOOLOGY. 223 



which the outermost one is widest. Outside this, and continuous in the row, 

 is a long papilla which stretches upward into the mouth-slit, and embraces 

 the second mouth-tentacle ; its base rests on the side mouth-shield and on 

 the first under arm-plate. This same piece is seen in other genera, Ophio- 

 coma, Ophiura, etc., and is usually reckoned among the true mouth-papilla?. 

 In Ophioglyplia it takes on a great development, and is the piece which car- 

 ries the scales of the mouth-tentacle, and which gives the forked look to the 

 mouth-slit. In the species under consideration it may cany a sort of lobe or 

 articulated scale. Five short, flat, rounded teeth, the uppermost one a little 

 longer and sharper. Mouth-shields rounded heart-shape ; rather wider than 

 long, standing close to the mouth-papilhe ; length to breadth 2.5: 3. Sup- 

 plementary mouth-shields semicircular and about half the size of the mouth- 

 shields. Side mouth-shields very small and wedged between the first under 

 arm-plate and the mouth-shield. Under arm-plates strongly overlapping, 

 bounded without by a broken curve and by a re-entering curve within ; 

 length to breadth, within disk, .G : .8. The first plate has a broad diamond 

 shape, and, between it and the second, are two large pores. The side arm- 

 plates cover nearly one half the, height of the arm at its base, the rest being 

 occupied by the upper arm-plates, which there are considerably arched, have 

 a wavy outer side, and a length to breadth as .6 : 3. A little farther out, the 

 upper arm-plates are lower and less arched. Disk flat and round, but embrac- 

 ing the base of each arm by a forked projection. With the exception of the 

 radial shields and shields of the mouth, it is closely granulated; about eight 

 grains in the length of a mm. This granulation is, however, easily rubbed 

 off, and then the coarse swollen scales of the disk maybe seen; among 

 which there are along the edge of the disk, in each interbrachial space, about 

 six imbricated plates, making a close row between outer ends of the radial 

 shields, which are large and conspicuous, oval in shape, and having a length 

 to breadth of 4 : 2. Arm-spines near disk, ten or eleven, small, slightly ta- 

 pering, somewhat flattened, a little rounded, about two thirds of the length 

 of a side arm-plate ; the lowest one scarcely longer than the rest. Two flat, 

 oval tentacle-scales ; the one which lies at the base of the lowest arm-spine 

 is smaller, as usual, but has its end rounded and not cut square off. 



Color, in alcohol, light yellowish brown above, with, lines and patches of 

 darker, and with darker specks on the upper arm-plates ; below, the under 

 arm-plates and mouth-region are white. 



This species, by its conspicuous radial shields and its arms widened next 

 the disk, stands near P. stellata, from which it is easily distinguished by 

 more numerous arm-spines and differently shaped under arm-plates. 



C. Semper ; Philippines. 



