OPHITTEOIDEA FEOM TfiE KOREAJf SEAS. 



469 



Genus Ophiactis, Liitken. 



Ophiactis sex-eadta, Gruhe (sp.), Wiegm. Archiv^ 1857, p. 324, 

 under genus Ophiolepis. 



This species was described by Liitkeu subsequently as Opliiactis 

 Bernhardt ii, and figured by him in tab. iii. fig. 7, in his essay on 

 the AVest-Indian and Central-American OphiurcBy p. 263, in 

 noticing the species obtained by the corvette ' Gralathea ' from 

 Nicobar and Tahiti. 



The Korean specimen evidently belongs to this species ; and 

 thus the known distribution is from Zanzibar, Nicobar Islands, 

 Korean seas, Sandwich Islands, and south to Tahiti. 



Locality. Korean seas. Collected by Capt. St. John, E.N. 



In the British Museum. 



Ophiactis affii^is, sp. nov. Plates X. & XI. figs. 23, 24. 



The disk is circular in outline, without arm-notches ; there is a 

 medium-sized, circular, flat scale in the centre, around this a 

 number of others, which are smaller, forming an indefinite rosette ; 

 and a band of irregular-shaped scales passes outwards in each in- 

 terradial space, with one or tw^o rows on either side of smaller 

 scales. The radial shields extend halfway to the centre, are sepa- 

 rated by two scales, the outer of which is long and narrow, and 

 the inner, producing the greatest amount of divergence, shorter 

 and broader: the shields are nearly in opposition over the arms, 

 and separated within ; they are rather covered at the margins by 

 the scales of the disk, and are long, narrow, and broadest without. 

 The scales of the margin of the disk carry a few separate, rather 

 wide apart, stout, short spines ; there are more on the top of the 

 disk, but in the interbrachial spaces below the scaling is small, and 

 the spines become crowded, small, very short, thin, and numerous. 



The oral structures are small ; and four or five of the broad 

 lower arm-plates are within the range of the disk. 



The mouth-shields are small, triangular, very slightly broader 

 than long, broad, and slightly rounded aborally, where there is 

 attachment to a process continuous with the sides of the genera- 

 tive slit, bluntly angular, or more or less rounded within, and 

 produced at the sides. The madreporic plate is rounded and larger 

 than the others. The side mouth-shields do not meet within, but 

 are large, triangular, with rounded edges, and are at the oral side 

 of the mouth-shield ; they unite with their neiglibours on the 

 under part of the first arm-plate. 



