MOXOCfRArH OF JAPANESE OPHIUROIDEA. 17 



divided vertebra?, in the entire rudimentary dorsal arm plates and 

 in the conversion of all the arm spines into compound hooks ; 

 and in almost all characters, this genus retains more embryonal 

 features. 



OpJiiohyaliis gotoi Matsumoto. 



OpMohyalus gotoi : Matsumoto, Proc. Acad. Nat. Sei. Philadelphia, 

 LXVn, 1915, p. 48. 



Two specimens ; probably off Misaki. 



Diameter of disk 9 mm. Length of arms 28 mm. Width of 

 arms at base 1 mm. 



Disk pentagonal, with concave interbrachial borders, very flat, 

 covered by a very thin, naked skin. Marginal disk scales present 

 but very feeble. Radial shields very rudimentary, insignificant, 

 forming a continuous row with the marginal scales. Genital slits 

 very small, short, extending from the outer end of the adorai 

 shield to that of the second lateral arm plate. 



Oral shields large, triangular, with perfectly rounded lateral 

 angles, inner sides forming together a brace- shape, outer side 

 slightly concave ; two and a half times as wide as long. Adorai 

 shields large, triangular, very long, acutely tapered inwards, not 

 meeting with each other. Oral plates long and narrow. The 

 space encircled by the oral and adorai shields and oral plates is 

 strongly depressed. Three or four oral papilhe on either side, 

 thin, transparent and finely serrate along the free edge. Two or 

 three short, wide, flattened teeth, with rounded and finely serrate 

 ends. Deep in the oral slits, on either side, occurs one conical, 

 rough papilla. 



Arms slender, covered by a very thin, transparent skin. The 

 halves of the vertebra) are incompletely soldered together, except 



