26 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



The genus Ophiobrachion is perhaps nearest to the genus Ophio- 

 canops; its arm spines, seven or eight in number, are also converted 

 into compound hooks, but in the single known species the integument 

 on both surfaces of the disk is armed with spines, there are both 

 upper and under arm plates hidden under the integument, and the 

 tentacular pores are of large size. 



Type of the genus. — Ophiocanops fugiens, new species. 



OPHIOCANOPS FUGIENS, new species. 



Plate 2, figs. 4-17. 



Locality. — Albatross station 5174; vicinity of Jolo; Jolo Light 

 bearing E., 4.81 kilometers (2.6 miles) distant (lat. 6° 03' 45" N., 

 long. 120° 57' 00" E.) ; 36 meters (20 fathoms) ; March 5, 1908 ; crs. S. 



One specimen (Cat, No. 41080, U.S.N.M.). 



Description. — The diameter of the disk does not exceed 3 mm. The 

 arms are very long and narrow, reaching a length of from 35 mm. to 

 40 mm., and are rather strongly rolled up ; they are 1 mm. across at 

 the base, remaining of the same width for almost their entire length. 



The disk is rounded. The dorsal surface is covered with a smooth 

 and rather thick integument, dark purple in color, which shows 

 numerous small still darker spots, which are continued onto the dorsal 

 surface of the arms. Because of the great development of the adoral 

 plates, which extend quite to the periphery of the disk, the latter has, 

 if it may be so expressed, no ventral surface. I was not able to make 

 out the genital slits. 



The outlines of the mouth plates are very easily seen. The mouth 

 shields are extremely small, triangular, confined to the angle formed 

 outwardly by the two adoral plates of each pair, and scarcely visible 

 when the animal is viewed ventrally. The plate which bears the 

 madroporic opening, which is situated on the lateral surface of the 

 disk, is rounded and very large, and shows a large vertical furrow 

 (fig. 15). The adoral plates are extremely developed, very high and 

 broad, a little broader than high, with the borders and the angles 

 rounded (figs. 8, 14, 15) ; of themselves they cover a good part of the 

 ventral face of the disk. The oral plates are very much smaller, tri- 

 angular, a little higher than broad. The mouth papillae, three on 

 either side, are small and conical, with the point blunted; the un- 

 paired terminal papilla is a little more elongated. The teeth form a 

 column of six small conical pieces, which are elongated and spiniform 

 with the points rounded (fig. 14). 



The integument which covers the dorsal surface of the arms is at 

 first very thick and opaque, and shows dark spots similar to those 

 seen on the dorsal surface of the disk; it then becomes thinner and 

 lighter in color, and the dorsal surface of the underlying vertebral 



