212 ART. 2. — H. MATSÜMOTO : 



long as the disk radius, and about thrice as long as wide. Inter- 

 brachial ventral surfaces covered also by a soft naked skin. 

 Genital slits long, (lenital scales not very conspicuous unless 

 the specimen is dried, arranged in a row and overlapping one 

 another. 



Oral shields pentagonal, witli rounded angles, outer sides 

 longest, inner side a litt'e concave ; madreporic shields* mucli 

 larger and almost circular. Adorai shields triangular, with concave 

 adradial side, neither meeting radially nor intcrradially. There is 

 a more or less conspicuous depression between the oral plates, as 

 in OpJiiothrlx. Two oral papilla.' on either side of the oral, angle, 

 conical, blunt, very stout; the distal one arises from the adorai 

 shield, and is longer than the apical one. 



Arms exceedingly long, more tlxan tliirty times as long as the 

 disk diameter ; they are widest at about one-third of the entire 

 length of the arms from the base. Dorsal arm plates almost 

 oval, bounded within by two nearly straight lines forming a very 

 large and obtuse angle, and witliout by a curve, which is nearly 

 flat medially but very convex laterally ; about twice as wide as 

 long, successive plates slightly in contact. In the basal joints, they 

 are very small and separated by spaces which are covered by a 

 soft naked skin. T/ateral arm plates not very prominent, almost 

 covered over by the arm spines, not meeting al)Ove or below, nor 

 in contact on the sides but separated by a naked space. First 

 ventral arm plate very small, quadrangular, wider than long. 

 Those beyond quadrangular, wider than long, except the basal one 

 or two, which are as long as, or longer than, wide. They in- 

 crease in size, especially in width, outwards, and become pentagonal 

 beyond the disk, with large and obtuse inner angle, rounded outer 

 angles, and notched outer side ; the successive plates are separated 



