MONOGEArn OF JAPANESE OrHIUROlDE.A . 



193 



Numerous specimens ; Misaki. One specimen (belonging to Mr. E., 

 Saitô, Imperial Museum at Uyeno, Tokyo) ; Aomori Bay. 



Uladiwostock (Lütken). 



This species is very variable. The disk scales are often 

 coarse and very irregular. The primary plates are sometimes 

 visible. The oral shields are rhomboidal, with the inner sides 

 longer than the outer, and longer than wide ; so that in Lütken's 

 fig. 6b, the upper right one is most natural. The ratio of the 

 arm length to the disk diameter is greater in smaller specimens ; 



Fig. 52. Amphipholift koclm. a. From above. x8. h. From below. x8. c. Side view of 

 two arm joints near disk x 8. (?. From above. x6. e. From below. x6. /. Side %iew of 

 three arm joints near disk. x6. 



SO that the size contrast of the arms is not so striking between 

 two specimens, one of which is 4 mm. and the other is 7 mm. 

 across the disk. In the smaller specimens the disk is flat, sub- 



