MONOGliAPH or JAPANESE OPHIUKOIDEA. 321 



are absent ; but in tlie other tliey are indistinctly represented by 

 one or two small scales, separated from the oral shield by gran- 

 ules. The adorai shields are almost, and the oral plates entirely, 

 covered with granules, which are coarser and sparser than in the 

 outer parts. Eight or nine oral papilla? on either side ; the outer- 

 most two or three are large, flat, thin ; the second from the 

 outermost is the largest ; inner ones very small, somewhat conical, 

 obtuse. At the apex of the jaw, an unpaired infradental papilla 

 is often present. Five to seven teeth, irregular in shape and size, 

 with pointed or rounded ends, arranged in an irregular vertical 

 row. 



Arms long, stout, gradually tapered, with a rather sharp 

 dorsal ridge, triangular in transverse section. Dorsal arm plates 

 large, almost occupying the entire dorsal surface of the arm, 

 quadrangular, with rounded outer corners, a little wider without 

 than wdthin, much wider than long, three to four times as wide 

 as long, with a rather sharp ridge in the median line ; some of 

 them divided into several irregular pieces. Lateral arm plates 

 very low, less than half the height of the arm, meeting neither 

 above nor below. Ventral arm plates small, rhomboidal, with the 

 shorter diagonal parallel to the arm axis. The first plate is 

 almost as wide as, but much shorter than, the following. The 

 three or four plates beginning with the second have a median 

 keel, which is more prominent proximally both with regard to one 

 plate and to the arm as a whole. Arm spines four for the most 

 part, but three in the distal part, very short, flattened, lanceolate, 

 obtuse ; the lowest one is somewhat longer than the others. One 

 tentacle scale, large, oval, thin, flat ; adorai ones larger. 



Colour in alcohol light yellowish brown. 



This species is quite near to B. Jacertosa (Lyman), but 



