MONOGRAril OF JAPANESE OrHIUEOIDEA. 187 



with fine, imbricating scales, which aiv only slightly finer than 

 those of the dorsal side. Genital slits long. 



Oral shields rhomboidal, with very acute inner and rounded 

 lateral and onter angles, inner sides longer than the outer ; longer 

 than wide. Adorai shields triangular, long and narrow, wider 

 outwards than inwards, meeting with each other within. Three 

 oral papilla? on either side ; the inner two are rounded, while 

 the outermost one is very large, wide and operculiform. Teeth 

 quadrangular and stout. 



Dorsal arm plates triangular, with rounded angles and convex 

 sides, about one and a half times as wide as long, much shorter 

 than the corresponding arm joints, so that the successive plates 

 are separated from one another. Lateral arm plates rather low, 

 distinctly flared outwards, those of the two sides meeting with 

 each other both above and below. First ventral arm plate small, 

 triangular, with convex outer side, wider tlian long. Those l^eyond 

 pentagonal, with acute inner angle, outer lateral angles perfectly 

 rounded, inner sides straight, lateral sides concave, outer side 

 convex ; about as long as, or slightly longer than, wdde, widest at 

 the inner lateral angles. Three arm spines, conical, acute ; the 

 uppermost one is the longest, sliglitly shorter than, or hardly as 

 long as, the corresponding arm joint ; the middle one is the 

 stoutest, but not distinctly compressed ; the lowest one is the 

 shortest. Two small, oval, flat, leaf-like tentacle scales, of which 

 the adradial one is slightly larger than the abradial. 



Colour in alcohol white or light yellow. In life, the disk is 

 light reddish brown. 



I have compared these specimens with those of A. sqi/ainala 

 (Delle Chiaje) from Naples, and found only two trifling differences 

 between them. In the Japanese specimens, the arms are three to 



