20 



ART. 2. — H. MATSUMOTO : 



9%^M*-. 



the disk. The colour is i3urpUsh brown in alcohol, the disk being 



beantifnlly spotted with darker shades. 



The rudimentary dor- 

 sal arm plates are entire 

 and transparent at the 

 outer parts of the arms, 

 but are divided into two 

 or three opaque, secondary 

 plates in the basal arm 

 joints. The smallest speci- 

 men, with the disk diam- 

 eter of 3.5 mm., has 

 entire dorsal arm plates 

 throughout, and has only 

 one or two granule-like 

 oral papilloD on either side 

 and less flattened and not 

 serrate teeth, besides a 



Fig. 3. OphlomyX't audraUs. a. From above. x7. h. 

 From below. x7. c Side view of four arm joints t i i 



ne^r disk. x7. d. Dorsal view of two arm joints at VCry short aud Wide dlstal 

 the middle part, x 7. c. Young specimen ; from below. 

 xl4. 



within the oral slit. The 



papilla, situated deep 



second oral tentacle pores of the same specimen open outside the 

 oral slits, and the first ventral arm plates are comparatively large. 

 A specimen with the disk diameter of 4 mm. has three of the 

 jaws with typical papillation, and two papillated as in the smallest 

 specimen mentioned. Probably, the oral papilla3 next the apex of 

 the jaws are the first to appear, and the more distal ones are 

 formed later. The distal papilla of the smahest specimen is not a 

 true oral papilla, lying at a higher level than the ordinary ones. 

 It may be distinguished as the primary oral papilla in contrast to 



