MONOGRAPH OF JAPANESE OPHIUROIDEA. 261 



Amphiophiura Matsumoto, 1915. 



Disk high and arched, covered with very thick plates or 

 scales, among which the primaries are very conspicuous. Kadial 

 shields stout, joined in pairs. Genital papillas, as well as papillso 

 of arm combs, well developed, either spiniform or squarish. Oral 

 shields very large, oval, pyriform or trefoil- shaped. Arms moderate- 

 ly long, stout, cylindrical or higher than wide at the base, very 

 gradually tapered outwards, with blunt extremity. Dorsal arm 

 plates usually well developed, widely in contact with one another 

 in the free basal part of the arms. Lateral arm plates high. 

 Ventral arm plates of the basal arm joints quadrangular or axe- 

 shaped, in contact with one another. One to numerous arm 

 spines, short, peg-like. Tentacle pores large, with numerous scales. 



This genus includes (1) species with very large oral shields, 

 which almost entirely cover the interbrachial ventral surfaces, viz. 

 Ophioglypha hullata Wyville Thomson, 1873 (the genotype), 0. 

 convexa Lyman, 1878, 0. abdita Kœhlee, 1901, 0. insolita Kœhler, 

 1904, 0. improva Kcehler, 1904 ; (2) species with the interbrachial 

 ventral surfaces covered over by a very large central plate and very 

 stout genital scales, viz. 0. solida Lyman, 1883, 0. stellata Studee, 

 1883 (1882), 0. sciitata Lyman, 1883, 0. paupera Kœhlee, 1897, 0. 

 sorc?^Y<2 Kœhlee, 1897, 0. liherata Kœhlee, 1904, 0. urhana Kœhlee, 

 1904, 0. remota Kœhlee, 1904, 0. latro Kœhlee, 1904, Ophiura 

 œdiplax CïjX'rk, 1911, 0. pompophora Qi^m^k, 1911 ; (3) species with the 

 interbrachial ventral surfaces covered with many small plates or 

 scales, and with quadrangular ventral arm plates, viz. Ophioglypha 

 sculptilis LvikLAN, 1878, 0. lacazei Lyman, 1878, 0. lapidar ia Lyman, 

 1878, 0. undata Lyslan, 1878, 0. ponder osa Lyman, 187 8, 0. prisca 

 Kœhlee, 1904, 0. laudata Kœhlee, 1904, 0. distinda Kœhlee, 



