26 



AKT. 2. — H. MATSUMOTO 



parent scales. Radial shields very rudimentary, insignificant, lying 

 on the disk margin. Genital slit short and very small. 



Oral shields trian- 



^>. 



gular, with convex outer 

 border. Adorai shields 



Eig. 3. OxMosmilax mircibiUs. x20. a. From above. 

 h. From below, c. Side view of three arm joints 

 near disk. 



large, quadrangular, longer 

 than wide, wilder outwards 

 than inwards, fully meet- 

 ing with each other within. 

 Oral slits short, fairly 

 closed up. Single oral 

 papilla on either side, 

 stout, stumpy, conspicu- 

 ously thorny at tip, turn- 

 ed up ventrally, instead 

 of projecting towards the 

 oral slit. Two or three 

 dental papillae at the apex 

 of each jaw, similar in shape and size to the oral papilla, also 

 turned up ventrally. Teeth in a single vertical row, also stout, 

 stumpy and thorny at tip. Second oral tentacle pores opening 

 entirely outside the oral shts, each provided with a stumpy and 

 thorny papilla, which arises fi'om the adorai sliield. 



Arms more or less vertically coiled, covered by a thick skin. 

 Dorsal arm plates entirely absent. Lateral arm plates subventral, 

 strongly flared laterally. First ventral arm plate large, quadran- 

 gular, with rounded angles, slightly longer than wide, much 

 wider without than within. Those beyond larger, hexagonal, the. 

 inner and inner lateral sides being very short ; outer angles per- 

 fectly rounded ; as long as, or slightly longer than wide, feebly 



