MONOGRAPH OF JAPANESE OPHroEOIDEA. 249 



AA — Adorai shields oval ; one to three supplementary plates present 

 among the oral plates and adorai shields ; genital papiUse and arm 

 combs absent OpUurolepis. 



Aspidophiura Matsumoto, 1915. 



Disk rather high, flat, covered chiefly by the very stent 

 primaries and the very large radial shields, which are joined in 

 pairs almost by their entire length. Arm combs present, with 

 conical and acute papillae. Interbrachial ventral surfaces covered 

 with a very large central plate, besides the very stout genital 

 scales. Oral shields large, peculiar in shape, with a beak-Hke 

 inner process. Oral papilla3 soldered together. Arms strongly 

 knotted, with long arm joints. Dorsal arm plates rudimentary or 

 absent. Lateral arm plates well developed, flared ; those of the 

 two sides meeting both above and below. Ventral arm plates 

 small, rhomboidal or triangular. Three arm spines, conical, usual- 

 ly acute. Tentacle pores rather rudimentary, present only in 

 several proximal arm joints. A single tentacle scale to each pore 

 or none beyond the second arm joint. 



This genus includes Ophioglypha minuta Lyman, 1878, and 0. 

 forhesi Duncan, 1789 {=Ophiura glyptoclisca Claek, 1911), besides 

 the genotype, Aspidophiura loatasei Matsumoto, 1915. 



This genus stands rather between the solida-groxip of Am- 

 pliiophiura and Anthophiura, but differs from the former in the 



three basal arm joints ; first ventral arm plate axe-shaped, separated from the next 



plate Uomalophiura. 



aa' — Disk scales usually numerous and fine ; second oral tentacle pores opening more or less 

 inside the oral slits; tentacle pores not confined to a few basal arm joints; first ventral 

 arm plate usually wider than long, and usually in contact with the nest plate.... 



Ophiura, rest. 



In my opinion. Uomalophiura is close to the Irrorata-gTuow}-) of Ophiura, being however more 

 psedomorphic in certain structures. 



